The 'jquery.arrowSteps' ResourceLoader module is only used by UploadWizard and was originally developed in tandem with UploadWizard, then moved to core for no good reason (r108960). Nothing else uses it; we should move it back. And once we do, we should remove all the functionality that UW does not use, and all the styles it overrides (which is probably most of the module).
|mediawiki/core : master||Deprecate jquery.arrowSteps module|
|mediawiki/core : wmf/1.28.0-wmf.19||Revert "Remove jquery.arrowSteps module"|
|mediawiki/core : master||Revert "Remove jquery.arrowSteps module"|
|mediawiki/core : master||Remove jquery.arrowSteps module|
|mediawiki/extensions/UploadWizard : master||Add jquery.arrowSteps from mw core|
Also used on Commons (https://commons.wikimedia.org/wiki/MediaWiki:WatchlistMessageCreator.js). Well, they could use it under the new name, but "nothing else uses it" is definitely wrong.
Well, I used it because it was there, not because it was sensible to use. I'll probably update my script today to remove the usage of jquery.arrowSteps completely, so if you think those two instances of usage I found were the only ones feel free just to keep the module removed.
But the deprecated key in a module definition is there for a purpose, and should be used as such in future deprecations before any removal.
Is there a hint for replacement? The gadget on https://commons.wikimedia.org/wiki/Help:Watchlist_messages is not working anymore. That all seems are steps backward. Than I copy all the module also in to the script.
PS: The gadget works now again, I used the module copy of the UW.