Strange MySQL database that I can't select

I am investigating a web site server (CentOS release 6.3) that runs the traditional lamp stack; I am getting the following output my MySQL; mysql> show databases; +--------------------+ | Database | +--------------------+ | information_schema | | #mysql50#.config | | webtestdb | | mysql | | test | | websitedb | +--------------------+ 6 rows in set (0.00 sec) What is "#mysql50#.config"? Also, I can

[rsakamot]

"This is nothing but a folder/file in database directory."

[katsuren]

#mysql50# の消し方、mysql の datadir の調べ方