$ git clone -n https://src.fedoraproject.org/rpms/bouncycastle.git /var/lib/mock/f40-build-2110409-50653/root/chroot_tmpdir/scmroot/bouncycastle
Cloning into '/var/lib/mock/f40-build-2110409-50653/root/chroot_tmpdir/scmroot/bouncycastle'...
$ git fetch origin 55337f97f74735a92d1656f6a61f3756aa963ce0:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/bouncycastle
 * [new ref]         55337f97f74735a92d1656f6a61f3756aa963ce0 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 55337f9 Build bcjmail (dependencies now available in Fedora)