All bugs categorized as 2.3-HEAD apply to 2.5-HEAD, so I have simply renamed the tag.
There is no such entity 2.1-HEAD, as it became 2.2.0... but that category is a mishmash of 2.0 specific bugs, 2.2 specific bugs, and those that still apply to 2.5-HEAD. Anyone who is willing to help out, I'd love to delete this tag as well, just as soon as this version bug list is empty; https://issues.apache.org/bugzilla/buglist.cgi?version=2.1-HEAD;product=Apache%20httpd-2
