The phpMyAdmin support page points to stackoverflow.com and serverfault.com as the sole (non-bug related) support mechanism:
Effective September 1st, 2013, support for questions directly related to phpMyAdmin has moved to stackoverflow. All prior support mechanisms have been phased out.
Questions about server issues (web server configuration, "404 - Not Found" error, etc), should be asked on serverfault.com.
The way of reporting (security) bugs and adding feature requests will be unaffected.
Since usage of DBA tools
- are considered topical on DBA
- art not topical on ServerFault (questions about installing/configuring the tools are topical, but not usage)
- StackOverflow really isn't the right place for most phpMyAdmin usage questions, unless it has to do with software development
- Usually don't fit into the class of questions that are on-topic on Webmasters
I think that DBA is the right SE site to direct phpMyAdmin usage questions, as opposed to SO, which is where they're being directed now. (At least by the phpMyAdmin support page.)