Previously, oplog entries for writes to time-series collections could be identified through the "system.buckets" collection prefix. With viewless time-series collections, an oplog entry for a write to a time-series collection cannot currently be discerned from writes to regular collections.

We want to be able to identify oplog entries for time-series collections (for example, to currently prevent change streams from operating on time-series collections, etc). One approach could be to add a new field in the oplog entry for writes to viewless time-series collections.