- Pre-populate room data used in experimental [MSC3575](https://github.com/matrix-org/matrix-spec-proposals/pull/3575) Sliding Sync `/sync` endpoint for quick filtering/sorting. ([\#17652](https://github.com/element-hq/synapse/issues/17652)) - Speed up sliding sync by reducing amount of data pulled out of the database for large rooms. ([\#17683](https://github.com/element-hq/synapse/issues/17683))