This may be a daft question, but on the MySQL release notes, a lot of them are followed by BUG Reference numbers. But most of these BUGS don't exist when you search for them at bugs.mysql.com.
InnoDB: A full-text query raised an assertion. Under certain circumstances, DDL operations such as ALTER TABLE ... RENAME caused full-text auxiliary tables to be removed on server restart. (Bug #13651665
Despite my best efforts I can't find out where to find these BUGS. Can anyone point me at the right location?