$ git clone -n https://src.fedoraproject.org/rpms/gnucash.git /var/lib/mock/f39-build-1626249-39260/root/chroot_tmpdir/scmroot/gnucash
Cloning into '/var/lib/mock/f39-build-1626249-39260/root/chroot_tmpdir/scmroot/gnucash'...
$ git fetch origin be6132f27634ab47f66d01bc38f66b33ed46c287:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/gnucash
 * [new ref]         be6132f27634ab47f66d01bc38f66b33ed46c287 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at be6132f 5.4