The intent is to always pack the latest stable MariaDB software into Fedora.
MariaDB series
MariaDB 10.0 - until Fedora 23
MariaDB 10.1 - until Fedora 26
MariaDB 10.2 - current (F27, F28, Rawhide)
MariaDB 10.3 - in developement (COPR)
MariaDB versions
There is a lot of work being done in both Fedora and by upstream developers.
New version of MariaDB is released approximately every month or two.
The packaging process usually takes from a few days up to two weeks, depends on issues encountered.
Connectors
Beginning from Fedora 28, mariadb-connector-c is the default package that should be used by all of the client software.
This package now contains the client library, while it was removed from the mariadb package.
Also mariadb-connector-c-devel package should contain everything needed for building the client software against mariadb.
Only very very few cases needs mariadb-devel package, such as custom server plugins or embedded applications.
For ODBC there is mariadb-connector-odbc package.
For Java there is mariadb-java-client package.
Other software
Since MariaDB is very compatible with MySQL, most of the mysql connectors could be used with mariadb and vice versa.
I also try to keep combinations of mariadb and mysql installable (f.e. mariadb-server and community-mysql client)