This is a list of known events and parameters; please add to it if you're going
to add events to the MediaWiki code.
+'AbortAutoAccount': Return false to cancel automated local account creation, where normally authentication against an external auth plugin would be creating a local account.
+$user: the User object about to be created (read-only, incomplete)
+&$abortMsg: out parameter: name of error message to be displayed to user
+
'AbortAutoblock': Return false to cancel an autoblock.
$autoblockip: The IP going to be autoblocked.
$block: The block from which the autoblock is coming.
&$retval: a LoginForm class constant to return from authenticateUserData();
default is LoginForm::ABORTED. Note that the client may be using
a machine API rather than the HTML user interface.
+&$msg: the message identifier for abort reason (new in 1.18, not available before 1.18)
'AbortMove': allows to abort moving an article (title)
$old: old title
$err: error message
$reason: the reason for the move (added in 1.13)
-'AbortNewAccount': Return false to cancel account creation.
+'AbortNewAccount': Return false to cancel explicit account creation.
$user: the User object about to be created (read-only, incomplete)
-$message: out parameter: error message to display on abort
+&$msg: out parameter: name of error message to display on abort
+
+'ActionBeforeFormDisplay': before executing the HTMLForm object
+$name: name of the action
+&$form: HTMLForm object
+$article: Article object
+
+'ActionModifyFormFields': before creating an HTMLForm object for a page action;
+ allows to change the fields on the form that will be generated
+$name: name of the action
+&$fields: HTMLForm descriptor array
+$article: Article object
'AddNewAccount': after a user account is created
$user: the User object that was created. (Parameter added in 1.7)
$sRevCount: Number of sucessfully imported revisions
$pageInfo: associative array of page information
-'AfterUserMessage': After a user message has been left, this hook is
-called to take care of any cleanup.
-$user: The user who we left the message for.
-$article: The article the message was left on.
-$subject: The subject of the message
-$text: The text of the message.
-$signature: The signature we used.
-$summary: The edit summary.
-$editor: The editor that performed the edit.
-
'AjaxAddScript': Called in output page just before the initialisation
of the javascript ajax engine. The hook is only called when ajax
is enabled ( $wgUseAjax = true; ).
$tokenFunctions array and return true (returning false makes no sense)
$tokenFunctions: array(action => callback)
+'APIQuerySiteInfoGeneralInfo': use this hook to add extra information to
+the sites general information.
+$module: the current ApiQuerySiteInfo module
+&$results: array of results, add things here
+
'APIQueryUsersTokens': use this hook to add custom token to list=users.
Every token has an action, which will be used in the ustoken parameter
and in the output (actiontoken="..."), and a callback function which
$tokenFunctions array and return true (returning false makes no sense)
$tokenFunctions: array(action => callback)
+'ApiRsdServiceApis': Add or remove APIs from the RSD services list.
+Each service should have its own entry in the $apis array and have a
+unique name, passed as key for the array that represents the service data.
+In this data array, the key-value-pair identified by the apiLink key is
+required.
+&$apis: array of services
+
'ArticleAfterFetchContent': after fetching content of an article from
the database
$article: the article (object) being loaded from the database
$output: the OutputPage object ($wgOut)
&$reason: the reason (string) the article is being deleted
+'ArticleContentOnDiff': before showing the article content below a diff.
+Use this to change the content in this area or how it is loaded.
+ $diffEngine: the DifferenceEngine
+ $output: the OutputPage object ($wgOut)
+
'ArticleDelete': before an article is deleted
$article: the article (object) being deleted
$user: the user (object) deleting the article
$article: article (object) that data will be loaded
$fields: fileds (array) to load from the database
+'ArticlePrepareTextForEdit': called when preparing text to be saved
+$article: the article being saved
+$popts: parser options to be used for pre-save transformation
+
'ArticleProtect': before an article is protected
$article: the article being protected
$user: the user doing the protection
&$sectionanchor: The section anchor link (e.g. "#overview" )
&$extraq: Extra query parameters which can be added via hooked functions
+'ArticleViewFooter': After showing the footer section of an ordinary page view
+$article: Article object
+
'ArticleViewHeader': Before the parser cache is about to be tried for article
viewing.
&$article: the article
Change $bad and return false to override. If an image is "bad", it is not
rendered inline in wiki pages or galleries in category pages.
-'BeforeGalleryFindFile': before an image is fetched for a gallery
-&$gallery,: the gallery object
-&$nt: the image title
-&$time: image timestamp
-
'BeforeInitialize': before anything is initialized in performRequestForTitle()
&$title: Title being used for request
&$article: The associated Article object
&$out: OutputPage object
&$skin: Skin object
+'BeforeParserFetchFileAndTitle': before an image is rendered by Parser
+$parser: Parser object
+$nt: the image title
+&$time: the image timestamp (use '0' to force a broken thumbnail)
+&$sha1: image base 36 sha1 (used to specify the file, $nt will be ignored if this is set)
+&$descQuery: query string to add to thumbnail URL
+
'BeforeParserFetchTemplateAndtitle': before a template is fetched by Parser
-&$parser: Parser object
-&$title: title of the template
+$parser: Parser object
+$title: title of the template
&$skip: skip this template and link it?
&$id: the id of the revision being parsed
-'BeforeParserMakeImageLinkObj': before an image is rendered by Parser
-&$parser: Parser object
-&$nt: the image title
-&$skip: skip this image and link it?
-&$time: the image timestamp
-
'BeforeParserrenderImageGallery': before an image gallery is rendered by Parser
&$parser: Parser object
&$ig: ImageGallery object
+'BeforeWelcomeCreation': before the welcomecreation message is displayed to a newly created user
+&$welcome_creation_msg: MediaWiki message name to display on the welcome screen to a newly created user account
+&$injected_html: Any HTML to inject after the "logged in" message of a newly created user account
+
+'BitmapHandlerTransform': before a file is transformed, gives extension the
+possibility to transform it themselves
+$handler: BitmapHandler
+$image: File
+&$scalerParams: Array with scaler parameters
+&$mto: null, set to a MediaTransformOutput
+
'BlockIp': before an IP address or user is blocked
$block: the Block object about to be saved
$user: the user _doing_ the block (not the one being blocked)
'DatabaseOraclePostInit': Called after initialising an Oracle database
&$db: the DatabaseOracle object
+'Debug': called when outputting a debug log line via wfDebug() or wfDebugLog()
+$text: plaintext string to be output
+$group: null or a string naming a logging group (as defined in $wgDebugLogGroups)
+
'NewDifferenceEngine': Called when a new DifferenceEngine object is made
$title: the diff page title (nullable)
&$oldId: the actual old Id to use in the diff
the link, like "§ion=$section"
$tooltip: The default tooltip. Escape with htmlspecialchars() before using.
By default, this is wrapped in the 'editsectionhint' message.
-$result: The HTML to return, prefilled with the default plus whatever other
+&$result: The HTML to return, prefilled with the default plus whatever other
changes earlier hooks have made
+$lang: The language code to use for the link in the wfMsg* functions
'EditFilter': Perform checks on an edit
$editor: Edit form (see includes/EditPage.php)
$editPage: EditPage object
'EditPage::attemptSave': called before an article is
-saved, that is before insertNewArticle() is called
+saved, that is before Article::doEdit() is called
$editpage_Obj: the current EditPage object
'EditPage::importFormData': allow extensions to read additional data
$title: Title being linked to
$section: Section to link to
$link: Default link
-$result: Result (alter this to override the generated links)
+&$result: Result (alter this to override the generated links)
+$lang: The language code to use for the link in the wfMsg* functions
'EmailConfirmed': When checking that the user's email address is "confirmed"
$user: User being checked
$editToken: The user's edit token.
&$hookErr: Out-param for the error. Passed as the parameters to OutputPage::showErrorPage.
+'ExtensionTypes': called when generating the extensions credits, use this to change the tables headers
+&$extTypes: associative array of extensions types
+
'FetchChangesList': When fetching the ChangesList derivative for
a particular user
-&$user: User the list is being fetched for
+$user: User the list is being fetched for
&$skin: Skin object to be used with the list
&$list: List object (defaults to NULL, change it to an object
instance and return false override the list derivative used)
$user: user who performed the undeletion
$reason: reason
-'FormatUserMessage': Hook to format a message if you want to override
-the internal formatter.
-$subject: Title of the message.
-&$text: Text of the message.
-$signature: Signature that they would like to leave.
-
'GetAutoPromoteGroups': When determining which autopromote groups a user
is entitled to be in.
&$user: user to promote.
$url: string value as output (out parameter, can modify)
$query: query options passed to Title::getLocalURL()
+'GetMetadataVersion': modify the image metadata version currently in use. This is
+ used when requesting image metadata from a ForiegnApiRepo. Media handlers
+ that need to have versioned metadata should add an element to the end of
+ the version array of the form 'handler_name=version'. Most media handlers
+ won't need to do this unless they broke backwards compatibility with a
+ previous version of the media handler metadata output.
+&$version: Array of version strings
+
'GetPreferences': modify user preferences
$user: User whose preferences are being modified.
&$preferences: Preferences description array, to be fed to an HTMLForm object
'getUserPermissionsErrorsExpensive': Absolutely the same, but is called only
if expensive checks are enabled.
-'HTMLCacheUpdate::doUpdate': After cache invalidation updates are inserted
-into the job queue.
-$title: Title object, pages linked to this title are purged.
-
'ImageBeforeProduceHTML': Called before producing the HTML created by a wiki
image insertion. You can skip the default logic entirely by returning
false, or just modify a few things using call-by-reference.
$target: Title/string of redirect target
$article: Article object
+'InterwikiLoadPrefix': When resolving if a given prefix is an interwiki or not.
+Return true without providing an interwiki to continue interwiki search.
+$prefix: interwiki prefix we are looking for.
+&$iwData: output array describing the interwiki with keys iw_url, iw_local,
+ iw_trans and optionally iw_api and iw_wikiid.
+
'InternalParseBeforeLinks': during Parser's internalParse method before links
but after noinclude/includeonly/onlyinclude and other processing.
&$parser: Parser object
$specialPageAliases: associative array of magic words synonyms
$lang: laguage code (string)
+'LanguageGetTranslatedLanguageNames': Provide translated language names.
+&$names: array of language code => language name
+$code language of the preferred translations
+
'LinkBegin': Used when generating internal and interwiki links in
Linker::link(), before processing starts. Return false to skip default proces-
sing and return $ret. See documentation for Linker::link() for details on the
expected meanings of parameters.
$skin: the Skin object
$target: the Title that the link is pointing to
-&$text: the contents that the <a> tag should have (raw HTML); null means "de-
+&$html: the contents that the <a> tag should have (raw HTML); null means "de-
fault"
&$customAttribs: the HTML attributes that the <a> tag should have, in associa-
tive array form, with keys and values unescaped. Should be merged with de-
'LinkEnd': Used when generating internal and interwiki links in Linker::link(),
just before the function returns a value. If you return true, an <a> element
-with HTML attributes $attribs and contents $text will be returned. If you re-
+with HTML attributes $attribs and contents $html will be returned. If you re-
turn false, $ret will be returned.
$skin: the Skin object
$target: the Title object that the link is pointing to
$options: the options. Will always include either 'known' or 'broken', and may
include 'noclasses'.
-&$text: the final (raw HTML) contents of the <a> tag, after processing.
+&$html: the final (raw HTML) contents of the <a> tag, after processing.
&$attribs: the final HTML attributes of the <a> tag, after processing, in asso-
ciative array form.
&$ret: the value to return if your hook returns false.
&$revert: string that is displayed in the UI, similar to $comment.
$time: timestamp of the log entry (added in 1.12)
-'LogPageValidTypes': action being logged.
-DEPRECATED: Use $wgLogTypes
-&$type: array of strings
-
-'LogPageLogName': name of the logging page(s).
-DEPRECATED: Use $wgLogNames
-&$typeText: array of strings
-
-'LogPageLogHeader': strings used by wfMsg as a header.
-DEPRECATED: Use $wgLogHeaders
-&$headerText: array of strings
-
-'LogPageActionText': strings used by wfMsg as a header.
-DEPRECATED: Use $wgLogActions
-&$actionText: array of strings
+'MaintenanceRefreshLinksInit': before executing the refreshLinks.php maintenance script
+$refreshLinks: RefreshLinks object
'MagicWordMagicWords': When defining new magic word.
DEPRECATED: use $magicWords in a file listed in
$variableIDs: array of strings
'MakeGlobalVariablesScript': called right before Skin::makeVariablesScript
-is executed
+is executed. Ideally, this hook should only be used to add variables that
+depend on the current page/request; static configuration should be added
+through ResourceLoaderGetConfigVars instead.
&$vars: variable (or multiple variables) to be added into the output
of Skin::makeVariablesScript
$wcOnlySysopsCanPatrol: config setting indicating whether the user
must be a sysop to patrol the edit
-'MathAfterTexvc': after texvc is executed when rendering mathematics
-$mathRenderer: instance of MathRenderer
-$errmsg: error message, in HTML (string). Nonempty indicates failure
- of rendering the formula
-
'MediaWikiPerformAction': Override MediaWiki::performAction().
Use this to do something completely different, after the basic
globals have been set up, but before ordinary actions take place.
"SkinTemplate"-type skins.
$tools: array of tools
+'BaseTemplateToolbox': Called by BaseTemplate when building the $toolbox array
+and returning it for the skin to output. You can add items to the toolbox while
+still letting the skin make final decisions on skin-specific markup conventions
+using this hook.
+&$sk: The BaseTemplate base skin template
+&$toolbox: An array of toolbox items, see BaseTemplate::getToolbox and
+ BaseTemplate::makeListItem for details on the format of individual
+ items inside of this array
+
'NewRevisionFromEditComplete': called when a revision was inserted
due to an edit
$article: the article edited
$parserOutput: the parserOutput (object) that corresponds to the page
$text: the text that will be displayed, in HTML (string)
-'OutputPageBodyAttrs': called when OutputPage::headElement is creating the body
+'OutputPageBodyAttributes': called when OutputPage::headElement is creating the body
tag to allow for extensions to add attributes to the body of the page they might
need. Or to allow building extensions to add body classes that aren't of high
enough demand to be included in core.
loader request or generating HTML output.
&$resourceLoader: ResourceLoader object
+'ResourceLoaderGetStartupModules': Run once the startup module is being generated. This allows you
+to add modules to the startup module. This hook should be used sparingly since any module added here
+will be loaded on all pages. This hook is useful if you want to make code available to module loader
+scripts.
+
'RawPageViewBeforeOutput': Right before the text is blown out in action=raw
&$obj: RawPage object
&$text: The text that's going to be the output
-'RecentChange_save': called at the end of RecenChange::save()
+'RecentChange_save': called at the end of RecentChange::save()
$recentChange: RecentChange object
+'ResourceLoaderGetConfigVars': called at the end of
+ResourceLoaderStartUpModule::getConfig(). Use this to export static
+configuration variables to JavaScript. Things that depend on the current
+page/request state must be added through MakeGlobalVariablesScript instead.
+&$vars: array( variable name => value )
+
'RevisionInsertComplete': called after a revision is inserted into the DB
&$revision: the Revision
$data: the data stored in old_text. The meaning depends on $flags: if external
'SetupAfterCache': Called in Setup.php, after cache objects are set
-'SetupUserMessageArticle': Called in User::leaveUserMessage() before
-anything has been posted to the article.
-$user: The user who we left the message for.
-&$article: The article that will be posted to.
-$subject: The subject of the message
-$text: The text of the message.
-$signature: The signature we used.
-$summary: The edit summary.
-$editor: The editor that performed the edit.
-
'ShowMissingArticle': Called when generating the output for a non-existent page
$article: The article object corresponding to the page
'SiteNoticeBefore': Before the sitenotice/anonnotice is composed
&$siteNotice: HTML returned as the sitenotice
+$skin: Skin object
Return true to allow the normal method of notice selection/rendering to work,
or change the value of $siteNotice and return false to alter it.
'SiteNoticeAfter': After the sitenotice/anonnotice is composed
&$siteNotice: HTML sitenotice
+$skin: Skin object
Alter the contents of $siteNotice to add to/alter the sitenotice/anonnotice.
'SkinAfterBottomScripts': At the end of Skin::bottomScripts()
&$link: overridable HTML link to be passed into the message as $1
&$forContent: overridable flag if copyright footer is shown in content language.
+'SkinGetPoweredBy'
+&$text: additional 'powered by' icons in HTML.
+Note: Modern skin does not use the MediaWiki icon but plain text instead
+$skin: Skin object
+
'SkinSubPageSubtitle': At the beginning of Skin::subPageSubtitle()
&$subpages: Subpage links HTML
$skin: Skin object
+$out: OutputPage object
If false is returned $subpages will be used instead of the HTML
subPageSubtitle() generates.
If true is returned, $subpages will be ignored and the rest of
subPageSubtitle() will run.
-'SkinTemplateBuildContentActionUrlsAfterSpecialPage': after the single tab
-when showing a special page
-$sktemplate: SkinTemplate object
-$content_actions: array of tabs
-
'SkinTemplateBuildNavUrlsNav_urlsAfterPermalink': after creating the
"permanent link" tab
$sktemplate: SkinTemplate object
$nav_urls: array of tabs
-'SkinTemplateContentActions': Alter the "content action" links in SkinTemplates
-&$content_actions: Content actions
-[See http://svn.wikimedia.org/viewvc/mediawiki/trunk/extensions/examples/Content_action.php
-for an example]
-
-'SkinTemplateNavigation': Alter the structured navigation links in SkinTemplates
+Alter the structured navigation links in SkinTemplates, there are three of these hooks called in different spots.
+'SkinTemplateNavigation': Called on content pages after the tabs have been added but before before variants have been added
+'SkinTemplateNavigation::SpecialPage': Called on special pages after the special tab is added but before variants have been added
+'SkinTemplateNavigation::Universal': Called on both content and special pages after variants have been added
&$sktemplate: SkinTemplate object
&$links: Structured navigation links
This is used to alter the navigation for skins which use buildNavigationUrls such as Vector.
&$text: Link text.
&$result: Complete assoc. array if you want to return true.
-'SkinTemplateTabs': called when finished to build the actions tabs
-$sktemplate: SkinTemplate object
-$content_actions: array of tabs
-
'SkinTemplateToolboxEnd': Called by SkinTemplate skins after toolbox links have
been rendered (useful for adding more)
-$tools: array of tools
+$sk: The QuickTemplate based skin template running the hook.
'SoftwareInfo': Called by Special:Version for returning information about
the software
&$special: NewPagesPager object (subclass of ReverseChronologicalPager)
$opts: FormOptions object containing special page options
&$conds: array of WHERE conditionals for query
+&tables: array of tables to be queried
+&$fields: array of columns to select
+&$join_conds: join conditions for the tables
+
+'SpecialNewPagesFilters': called after building form options at NewPages
+$special: the special page object
+&$filters: associative array of filter definitions. The keys are the HTML name/URL parameters.
+Each key maps to an associative array with a 'msg' (message key) and a 'default' value.
'SpecialPage_initList': called when setting up SpecialPage::$mList, use this
hook to remove a core special page
$list: list (array) of core special pages
+'SpecialPasswordResetOnSubmit': when executing a form submission on Special:PasswordReset
+$users: array of User objects
+$data: array of data submitted by the user
+&$error: string, error code (message name) used to describe to error (out paramater).
+ The hook needs to return false when setting this, otherwise it will have no effect.
+
'SpecialRandomGetRandomTitle': called during the execution of Special:Random,
use this to change some selection criteria or substitute a different title
&$randstr: The random number from wfRandom()
&$title: If the hook returns false, a Title object to use instead of the
result from the normal query
+'SpecialRecentChangesFilters': called after building form options at RecentChanges
+$special: the special page object
+&$filters: associative array of filter definitions. The keys are the HTML name/URL parameters.
+Each key maps to an associative array with a 'msg' (message key) and a 'default' value.
+
'SpecialRecentChangesPanel': called when building form options in
SpecialRecentChanges
&$extraOpts: array of added items, to which can be added
&$join_conds: join conditions for the tables
$opts: FormOptions for this request
&$query_options: array of options for the database request
-&$select: String '*' or array of columns to select
+&$select: Array of columns to select
-'SpecialSearchGomatch': called when user clicked the "Go" button and the target
-exists
-&$title: title object generated from the text entred by the user
+'SpecialSearchGo': called when user clicked the "Go"
+&$title: title object generated from the text entered by the user
+&$term: the search term entered by the user
'SpecialSearchNogomatch': called when user clicked the "Go" button but the
target doesn't exist
-&$title: title object generated from the text entred by the user
+&$title: title object generated from the text entered by the user
'SpecialSearchProfiles': allows modification of search profiles
&$profiles: profiles, which can be modified.
+'SpecialSearchProfileForm': allows modification of search profile forms
+$search: special page object
+&$form: String: form html
+$profile: String: current search profile
+$term: String: search term
+$opts: Array: key => value of hidden options for inclusion in custom forms
+
+'SpecialSearchSetupEngine': allows passing custom data to search engine
+$search: special page object
+$profile: String: current search profile
+$engine: the search engine
+
'SpecialSearchResults': called before search result display when there
are matches
$term: string of search term
use this to change the tables headers
$extTypes: associative array of extensions types
+'SpecialWatchlistFilters': called after building form options at Watchlist
+$special: the special page object
+&$filters: associative array of filter definitions. The keys are the HTML name/URL parameters.
+Each key maps to an associative array with a 'msg' (message key) and a 'default' value.
+
'SpecialWatchlistQuery': called when building sql query for SpecialWatchlist
&$conds: array of WHERE conditionals for query
&$tables: array of tables to be queried
$pageid: database ID of the page that's been moved
$redirid: database ID of the created redirect
+'UndeleteForm::showHistory': called in UndeleteForm::showHistory, after a
+PageArchive object has been created but before any further processing is done.
+&$archive: PageArchive object
+$title: Title object of the page that we're viewing
+
+'UndeleteForm::showRevision': called in UndeleteForm::showRevision, after a
+PageArchive object has been created but before any further processing is done.
+&$archive: PageArchive object
+$title: Title object of the page that we're viewing
+
+'UndeleteForm::undelete': called un UndeleteForm::undelete, after checking that
+the site is not in read-only mode, that the Title object is not null and after
+a PageArchive object has been constructed but before performing any further
+processing.
+&$archive: PageArchive object
+$title: Title object of the page that we're about to undelete
+
'UndeleteShowRevision': called when showing a revision in Special:Undelete
$title: title object related to the revision
$rev: revision (object) that will be viewed
$uploadFormTextAfterSummary to inject text (HTML) either before
or after the editform.
-'UploadForm:BeforeProcessing': DEPRECATED! at the beginning of processUpload()
+'UploadForm:BeforeProcessing': at the beginning of processUpload()
$form: UploadForm object
Lets you poke at member variables like $mUploadDescription before the
file is saved.
+Do not use this hook to break upload processing. This will return the user to
+a blank form with no error message; use UploadVerification and
+UploadVerifyFile instead
'UploadCreateFromRequest': when UploadBase::createFromRequest has been called
$type: (string) the requested upload type
$ip: IP of the user who sent the message out
$u: the account whose new password will be set
+'UserAddGroup': called when adding a group; return false to override
+stock group addition.
+$user: the user object that is to have a group added
+&$group: the group to add, can be modified
+
'UserArrayFromResult': called when creating an UserArray object from a
database result
&$userArray: set this to an object to override the default object returned
'UserGetImplicitGroups': Called in User::getImplicitGroups()
&$groups: List of implicit (automatically-assigned) groups
+'UserGetLanguageObject': Called when getting user's interface language object
+$user: User object
+&$code: Langauge code that will be used to create the object
+
'UserGetReservedNames': allows to modify $wgReservedUsernames at run time
&$reservedUsernames: $wgReservedUsernames
'UserLoginForm': change to manipulate the login form
$template: SimpleTemplate instance for the form
-'UserLoginMailPassword': Block users from emailing passwords
-$name: the username to email the password of.
-&$error: out-param - the error message to return.
-
'UserLogout': before a user logs out
$user: the user object that is about to be logged out
$inject_html: Any HTML to inject after the "logged out" message.
$oldName: name of the user before logout (string)
+'UserRemoveGroup': called when removing a group; return false to override
+stock group removal.
+$user: the user object that is to have a group removed
+&$group: the group to be removed, can be modified
+
'UserRights': After a user's group memberships are changed
$user : User object that was changed
$add : Array of strings corresponding to groups added
&$timestamp: new timestamp, change this to override local email
authentification timestamp
-'WantedPages::getSQL': called in WantedPagesPage::getSQL(), can be used to
-alter the SQL query which gets the list of wanted pages
+'WantedPages::getQueryInfo': called in WantedPagesPage::getQueryInfo(), can be
+used to alter the SQL query which gets the list of wanted pages
&$wantedPages: WantedPagesPage object
-&$sql: raw SQL query used to get the list of wanted pages
+&$query: query array, see QueryPage::getQueryInfo() for format documentation
'WatchArticle': before a watch is added to an article
$user: user that will watch
$row: The database row for the revision.
$text: The revision text.
+'XMPGetInfo': Called when obtaining the list of XMP tags to extract. Can be used to add
+ additional tags to extract.
+&$items: Array containing information on which items to extract. See XMPInfo for details on the format.
+
+'XMPGetResults': Called just before returning the results array of parsing xmp data. Can be
+ used to post-process the results.
+&$data: Array of metadata sections (such as $data['xmp-general']) each section is an array of
+ metadata tags returned (each tag is either a value, or an array of values).
+
More hooks might be available but undocumented, you can execute
./maintenance/findhooks.php to find hidden one.