Both past and future. Some people asked for this. Maybe in the database, maybe as a flat file generated with a new support from https://github.com/calixteman/release-calendar/
Can you elaborate on this? It shouldn't be hard to export the past releases in some format, but I have doubts about implementing this future for the future releases.
Having at least the release dates (past and future) would be potentially great for some tools, don't you think? :) (dashboard and tooling)