This extension hook has no documentation on MediaWiki.org. Please improve MediaWiki by adding documentation to it. See Template:ExtensionHook for instructions on how to do it.

For examples of extensions using this hook, see Category:MassMessageJobBeforeMessageSent extensions . Category:Extension hooks#MassMessageJobBeforeMessageSent Category:Undocumented extension hooks#MassMessageJobBeforeMessageSent Category:Extension hooks provided by MassMessage Category:Extension hooks#MassMessageJobBeforeMessageSent Category:Undocumented extension hooks#MassMessageJobBeforeMessageSent Category:Extension hooks provided by MassMessage