To clarify, my comment was based on anecdotal discussions and interactions with users, issue reports, feature requests, user enthusiasm for new MySQL support/functionality vs relative lack of enthusiasm for new MariaDB support/functionality, etc.

The Skeema CLI is able to accurately identify your database version and flavor (which is necessary for its functionality), there is no notion of MariaDB registering itself as MySQL. But the CLI does not contain telemetry, so I don't have hard stats on MySQL vs MariaDB usage.