Both Special:RecentChanges and Special:Watchlist display a legend that explains what each tag means. Special:Contributions is lacking this legend.
Change 264942 abandoned by Thiemo Kreuz (WMDE):
Add legend to the Special:Contributions form
The request to have a legend on this special page might be valid, but the one line this patch suggests to add does not even work. Since there was no action here for almost 4 years, I'm going to archive this. It can still be accessed fro the ticket on Phabricator, if needed.
@Devirk: I am resetting the assignee of this task because there has not been progress lately (please correct me if I am wrong!). Resetting the assignee avoids the impression that somebody is already working on this task. It also allows others to potentially work towards fixing this task. Please claim this task again when you plan to work on it (via Add Action... → Assign / Claim in the dropdown menu) - it would be welcome. Thanks for your understanding!