$ git clone -n https://src.fedoraproject.org/rpms/j4-dmenu-desktop.git /var/lib/mock/f41-build-785986-13590/root/chroot_tmpdir/scmroot/j4-dmenu-desktop
Cloning into '/var/lib/mock/f41-build-785986-13590/root/chroot_tmpdir/scmroot/j4-dmenu-desktop'...
$ git fetch origin a251903113f10b3fe3ce342977ee44fd1a3e0788:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/j4-dmenu-desktop
 * [new ref]         a251903113f10b3fe3ce342977ee44fd1a3e0788 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at a251903 switch to newer snapshot