$ git clone -n https://src.fedoraproject.org/rpms/calibre.git /var/lib/mock/f40-build-2663145-66975/root/chroot_tmpdir/scmroot/calibre
Cloning into '/var/lib/mock/f40-build-2663145-66975/root/chroot_tmpdir/scmroot/calibre'...
$ git fetch origin 11856ff23253f1c2c0993694f9844a9f1c48879b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/calibre
 * [new ref]         11856ff23253f1c2c0993694f9844a9f1c48879b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 11856ff Update to 7.7.0. Fixes rhbz#2269518