$ git clone -n https://src.fedoraproject.org/rpms/exim-doc.git /var/lib/mock/f45-build-8549-390/root/chroot_tmpdir/scmroot/exim-doc
Cloning into '/var/lib/mock/f45-build-8549-390/root/chroot_tmpdir/scmroot/exim-doc'...
$ git fetch origin 205d995cc8ec2d343f62815a82b0e1ed81f110e6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/exim-doc
 * [new ref]         205d995cc8ec2d343f62815a82b0e1ed81f110e6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 205d995 Rebuilt for https://fedoraproject.org/wiki/Fedora_45_Mass_Rebuild