$ git clone -n https://src.fedoraproject.org/rpms/rust-bigdecimal.git /var/lib/mock/f40-build-2507352-61702/root/chroot_tmpdir/scmroot/rust-bigdecimal
Cloning into '/var/lib/mock/f40-build-2507352-61702/root/chroot_tmpdir/scmroot/rust-bigdecimal'...
$ git fetch origin b03dcffe5cdb09fdbcd03e91f93269aca8c1bee6:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-bigdecimal
 * [new ref]         b03dcffe5cdb09fdbcd03e91f93269aca8c1bee6 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at b03dcff Update to version 0.4.3; Fixes RHBZ#2267868