BSL Clarification: How to Count Servers

The newly-adopted Business Source License (BSL) replaces GPL for version 2.0 of MaxScale. This license contains the following text:

Use Limitation: Usage of the software is free when your application uses
the Software with a total of less than three database
server instances for production purposes.

To eliminate ambiguity, does the "less than three database servers" mean the application itself connects via MaxScale to three backend MariaDB servers?

What if the application connects only to one, which part of a larger replication topography? Does the whole of the replication topography count towards the "less than three" limit?

What about an application that connects to a single MySQL database via MaxScale, but leverages FEDERATED or SPIDER storage engines to connect that single MySQL database to other instances (perhaps not even MySQL servers)?

What about a single application runtime environment, with multiple "applications" each accessing different databases - but only one each?

If I have a single application that makes use of multiple "databases", but only one connects through MaxScale, do I still need to purchase a license?

Which "databases" count towards the limit? MySQL? MariaDB? Oracle? MS SQL? DB2? Derby? SQLite? MongoDB? Memcached? Hadoop Impala?