With new release of Debian, the default db is MariaDb and not Mysql.
I think it's time to update the server documentation here and here (updated 12 years ago).

With new release of Debian, the default db is MariaDb and not Mysql.

And not only on Debian
Distributions Which Include MariaDB
MariaDb is now the default db for ArchLinux, CentOs, Fedora, Mageia, Gentoo, Sabayon, Red Hat Enterprise, Suse, etc

MariaDb is now the default db for ArchLinux, CentOs, Fedora, Mageia, Gentoo, Sabayon, Red Hat Enterprise, Suse, etc

Also FreeBSD and OpenBSD use MariaDB as default

However the server code has not been written around MariaDB so someone would have to go through that and resolve all the inevitable warnings and errors that would occur when changing the db engine.

However the server code has not been written around MariaDB so someone would have to go through that and resolve all the inevitable warnings and errors that would occur when changing the db engine.

I know, i know. But i think this will be the future...
Admins are also migrating from Phyton 2 to Phyton 3, so it's time to update a LOT of documentation, like this