Official TokuDB Product Specs and Manuals are available on the Tokutek website. The page has links to the latest manuals, FAQ, and etc.... For example:

Version of the TokuDB plugin included in MariaDB

The version of TokuDB in your local MariaDB is available by querying the tokudb_version status variable. For example:

SHOW VARIABLES LIKE 'tokudb_version';

More information about TokuDB in MariaDB can be found on the following pages: