https://github.com/phpbb/phpbb3/pull/833 lists this topic as the RFC.
Please write a summary/spec for the changes made. This should include:
1. A list of user-visible changes. Can users do anything that was not previously possible? In other words, has any functionality been added that users would notice?
2. A list of (major) features that were changed. They could either have changed behavior or have a different implementation (plupload instead of whatever existed before) with the same UI. This is needed for testing the changes.
3. A list of (major) TODO items. Is there functionality missing that must be completed before the code that is already written is shippable? Is there functionality that is not strictly required but that would be extremely helpful? Are there any wishlist items that are not critical?