[jzb]

MySQL sold to Sun in 2008, which was then gobbled up by Oracle in 2009.

MariaDB is the fork, technically speaking. The distro switch took some time, probably in part because they wanted to wait and see if MariaDB would be suitable / sustainable.

Fedora and openSUSE switched to MariaDB in 2013, in part due to Oracle's license changes and changes to info published in CVEs and because they were considered easier to work with. (See: https://lists.fedoraproject.org/pipermail/devel-announce/201...)