Watchlist and recent changes should include a legend for the N, m, b, ± icons. They have tooltips, but that's not necessarily discoverable.
The Russian Wikipedia has a really nice one: https://ru.wikipedia.org/wiki/Служебная:Свежие_правки
Version: 1.22.0
Severity: enhancement
Whiteboard: gci2013 https://www.mediawiki.org/wiki/Google_Code-In#Candidate_tasks
See Also:
https://bugzilla.wikimedia.org/show_bug.cgi?id=43463