$ git clone -n https://src.fedoraproject.org/rpms/arc-theme.git /var/lib/mock/f39-build-1629203-39525/root/chroot_tmpdir/scmroot/arc-theme
Cloning into '/var/lib/mock/f39-build-1629203-39525/root/chroot_tmpdir/scmroot/arc-theme'...
$ git fetch origin 545c2008780d21c60b379728881660e747ccc098:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/arc-theme
 * [new ref]         545c2008780d21c60b379728881660e747ccc098 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 545c200 drop i686 to prevent failures on dependencies