public bug trackers are mostly used in the OSS community, and I don't know of any closed source software company using that. Don't get me wrong, bug trackers are fantastic (for Linux, Mozilla, Chrome...) but they mainly imply that the devs post on them together with the users reporting bugs and testing files, while the devs are sharing pieces of code in the open while attempting to resolve the bugs, and again, I doubt that a mainly closed source and commercial company like Avast can be interested. (on a side note, Avast 5 might integrate many oss but the core components are Avast, and closed source)