$ git clone -n https://src.fedoraproject.org/rpms/zathura-pdf-mupdf.git /var/lib/mock/f39-build-2462897-61444/root/chroot_tmpdir/scmroot/zathura-pdf-mupdf
Cloning into '/var/lib/mock/f39-build-2462897-61444/root/chroot_tmpdir/scmroot/zathura-pdf-mupdf'...
$ git fetch origin f6fabf132471c93dc79dce1f9a162cfe775831ad:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/zathura-pdf-mupdf
 * [new ref]         f6fabf132471c93dc79dce1f9a162cfe775831ad -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at f6fabf1 build against mupdf 1.23.3