This provides users who pre-publish their events ahead of time the same publishing time frame as those who don't pre-publish. The clock starts only once the file uploads happen.
Expiry dates for all currently published events have been recalculated accordingly as well.
On a related note, the timeframe for files going into "Deep Archive" has been updated to 3 months after upload.
For more information on event archiving check out this help article Archiving events for long periods of time.