On a self hosted git repository (untested on other set ups) navigate to a main repository view. i.e. /diffusion/7/
master branch as of 1/15, or rPea9cb0b625fb
On my Fedora 33 hosted phabricator instance (running git version 2.26.2 if that matters), after updating to the latest master on Friday 1/15 all git repository views were showing this error message
These errors weren’t present after updating on Wednesday 1/13. Given the timing, along with the changes in rPea9cb0b625fb I believe that commit is what caused the errors.