Gerrit 157497 added addHelpLink() feature. It could be documented better.
- It's not mentioned in RELEASE-NOTES-1.25 (the underlying indicator facility is).
- Its doxgen help doesn't document the parameters or mention the hardcoded //www.mediawiki.org/wiki/Special:MyLanguage/ URL path.
- The BoilerPlate extension's SpecialHelloWorld.php should show this working.
- It's not mentioned on mediawiki.org pages such as writing an extension, Category:Extension help, Project:PD Help, etc. (I'll work on this bit.)