The legacy mongos cursor manager (the "CursorCache") and the corresponding legacy query path are currently not used by default, though they currently remain available to the user (via --setParameter useClusterClientCursor=false). We are aiming to leave the code for this path in the server for 1-3 release candidates for a couple of reasons:

• In case any bugs discovered during the release process require re-enabling it for certain classes of queries before a stable release is shipped.
• To assist in performance diagnostics that compare the new path to the old path.

If no bugs are discovered, this code should be deleted before the stable release is shipped. The tasks for this ticket are as follows:

• Delete the 'useClusterClientCursor' global and setParameter.
• Delete the CursorCache class.
• Remove 'incomplete' from the LIBDEPS_TAGS list for libstore_possible_cursor.