how I can find revision that merges some dotted revno?

[Alexander Belchenko]

Use case:
I run annotate to see who and when introduce some changes to sources.
And annotate says me some dotted revno, e.g. 2568.1.1 (in bzr.dev).

I'd like to find in what mainline revision it was merged, to track down
what else changes was merged as well. Does we have any way to obtain
this information? May be some plugin already know how to do this?

Alexander