In MediaWiki core's ContentHandler "module", a lot of hooks and functions were deprecated in MediaWiki version 1.21 (1.21 was released in 2013 and 1.21 is unsupported since 2014). Many of these deprecated hooks and functions are still used in code bases (that's called "technical debt") and should be replaced. They were already cleaned up in MediaWiki extensions that are deployed on WMF sites, but other extensions were not taken care of yet. These extensions need cleaning up so that the deprecated functions can finally be removed from the MediaWiki core codebase in the end!
The commit message of your Gerrit patch(es) should include the line Bug: T151973.
This task is primarily designed for GCI students, but can be done by anyone if deemed appropriate.
* ArticleAfterFetchContent was replaced by ArticleAfterFetchContentObject * ArticleInsertComplete was replaced by PageContentInsertComplete * ArticleSave was replaced by PageContentSave * ArticleSaveComplete was replaced by PageContentSaveComplete * EditFilterMerged was replaced by EditFilterMergedContent * EditPageGetPreviewText was replaced by EditPageGetPreviewContent
Article::getContent() Article::doEdit() / WikiPage::doEdit() Revision::getText()
See also parent task: T145728