EventLogFixtures
The fixtures and hooks of the EventLog contract (EventLogSpec, the class a backend's test extends): the backend's hooks (createLog, refused, opensOneStorePerContext, createSnapshots, snapshotTailsOf), the streams a test appends (stream) and the suite's constants.
The contract's cases come in families, one class each: EventLogRecordCases, EventLogAccessCases, EventLogEntryCases, EventLogReadCases and EventLogBatchCases, then EventLogSpec with the uniqueness and concurrency cases. They form one chain, in that order, each extending the one before, because a class has one superclass and JUnit runs the cases a test class inherits. The order means nothing: every family reads only this class's fixtures, hooks and constants, never a member of the family it extends, so any order would run the same cases.
The suite's constants sit here, not on EventLogSpec as in the query contracts: the stores' own tests read TAIL_TIMEOUT_MS unqualified, so its companion is protected, and a parent class cannot read a protected member of its subclass's companion. What only the families read in it is internal.