$ git clone -n https://src.fedoraproject.org/rpms/rust-crypto-bigint.git /var/lib/mock/f39-build-1538112-36388/root/chroot_tmpdir/scmroot/rust-crypto-bigint
Cloning into '/var/lib/mock/f39-build-1538112-36388/root/chroot_tmpdir/scmroot/rust-crypto-bigint'...
$ git fetch origin 18430cb1f0cb51470920596d9441c7d4fb27dd26:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-crypto-bigint
 * [new ref]         18430cb1f0cb51470920596d9441c7d4fb27dd26 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 18430cb Update to version 0.5.3; Fixes RHBZ#2237332