Original title:
"cleanupOrphaned with secondaryThrottle is both w=2 and w=majority"

Original Description:

cleanupOrphaned uses a range deleter, which always waits up to an hour for a majority of the replica set to catch up before returning from deleteRange().

https://github.com/mongodb/mongo/blob/master/src/mongo/db/range_deleter_db_env.cpp#L121

cleanupOrphaned with the secondaryThrottle parameter also waits up to a minute after deleting each document for one secondary to replicate the delete (w=2).

https://github.com/mongodb/mongo/blob/master/src/mongo/db/dbhelpers.cpp#L405

This is an odd combination of not-quite-identical write concerns; I'm opening this ticket to investigate if this behavior is by design.