$ git clone -n https://src.fedoraproject.org/rpms/zathura-pdf-mupdf.git /var/lib/mock/f38-build-side-42-init-devel-1144490-30457/root/chroot_tmpdir/scmroot/zathura-pdf-mupdf
Cloning into '/var/lib/mock/f38-build-side-42-init-devel-1144490-30457/root/chroot_tmpdir/scmroot/zathura-pdf-mupdf'...
$ git fetch origin 5f1b10ef9dba7c1c498e7bdca5a2e2d9c22f9dc5:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/zathura-pdf-mupdf
 * [new ref]         5f1b10ef9dba7c1c498e7bdca5a2e2d9c22f9dc5 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 5f1b10e build against mupdf 1.22.1