Is there a bugzilla (or other tool) database that mere mortals can have (read-only) access to for bind?
No. The BIND 9 bug database is kept closed for a number of reasons. These include, but are not limited to, that the database contains proprietary information from people reporting bugs. The database has in the past and may in future contain unfixed bugs which are capable of bringing down most of the Internet’s DNS infrastructure. The release pages for each version contain up to date lists of bugs that have been fixed post release. That is as close as we can get to providing a bug database.