See discussion at Can't access https://reviews.llvm.org/ and No emails from phabricator since Nov 15 ; basically, Phabricator broke, and the maintainers decided to switch to the static archive instead of trying to fix it.
So the current state is:
- Phabricator is down.
- reviews.llvm.org points to the static archive. The static archive is known to be missing some content (Some reviews on reviews.llvm.org seem to be missing from the static archive)