$ git clone -n https://src.fedoraproject.org/rpms/rubygem-mime-types-data.git /var/lib/mock/f39-build-1458611-33074/root/chroot_tmpdir/scmroot/rubygem-mime-types-data
Cloning into '/var/lib/mock/f39-build-1458611-33074/root/chroot_tmpdir/scmroot/rubygem-mime-types-data'...
$ git fetch origin ac77ae4ee9b83618a961d9af7673d3e81901f180:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rubygem-mime-types-data
 * [new ref]         ac77ae4ee9b83618a961d9af7673d3e81901f180 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at ac77ae4 Rebuilt for https://fedoraproject.org/wiki/Fedora_39_Mass_Rebuild