* Development and maintenance of Phabricator has slowed down a lot.

* People were claiming phabricator was old-fashioned and confusing and hoping a merge-request based workflow would be more inviting

I'm the maintainer of one of the test projects that moved to our gitlab instance, and it's mostly fine, we're missing things in the merge request workflow, but have papered around that with labels (https://invent.kde.org/kde/krita/merge_requests), but we're still using phabricator for task management because it's so powerful for that that we cannot move that part of our workflow to gitlab yet.

From the conversations with the KDE team (they might chime in with more context), the main goals were:

- More accessible infrastructure for contributors

- Code review integration with git

- Streamlined infrastructure and tooling

- Good relationship and open communication channel with upstream (GitLab in this case)

https://gitlab.com/gitlab-org/gitlab-foss/issues/53206

> Maybe there were some discussions in some public mailing lists?

I believe there were some other threads as well, but for a start, here is one of the discussions on the kde-devel mailing list: https://marc.info/?t=155091510600001&r=1&w=2

https://gitlab.com/gitlab-org/gitlab-foss/issues/53206

Nothing on the mailing lists as far as I can tell.