I haven’t added mrt:moment@2.8.1, but it’s in my versions file and I can’t figure out why or what package is adding it.
I already explicitly added momentjs:moment, so now I have two copies of moment loading.
Is there a way to see a dependency map or something?
I’m afraid AutoForm may be the culprit in regard to mrt:moment – @aldeed uses Timezones, which hasn’t come out with official Meteor support yet.
What I do, when I’m wondering about dependencies or hooks or general ways to tweak and mold some package, is that I go look at the source. And the easiest way to do that, that I’ve come up with so far, is opening my .sublime-project file and commenting out the .meteor/local folder – containing, among other things, the complete build of your app – so that it’s no longer hidden in my project.
I then use the project wide search function (cmd+shift+f).
Most identifiers are pretty unique and that search is fast, so now that I’m used to doing it all the time, I can usually find an explanation for whatever puzzles me within a few seconds.
This is how I spend most of my days as a full-time Meteor developer, btw. I enjoy it thoroughly 
AutoForm has been using momentjs:moment for awhile now. It does use mrt:moment-timezone, too, but that’s a different package.
mrt:moment-timezone depends on mrt:moment, though? 
Anyway, probably won’t be so long till an official version comes out.