The primary way to report bug is to send e-mail to VRR
mailing list (see Developers' center). Long time we used the file TODO in the root source directory to maintain the list of bugs in various status.
Then it became clear, that a TODO is not enough and we installed the Bugzilla bug tracking system, available at http://vrr.ucw.cz/bugzilla/. All developers are granted access and can browse list of their bugs, change their status, write comments, report new bugs, etc.
All traffic from Bugzilla is mirrored into VRR mailing list and it is possible to reply to Bugzilla messages via e-mail. Just reply to vrrzilla@atrey.karlin.mff.cuni.cz instead of VRR list address.