$ git clone -n https://src.fedoraproject.org/rpms/rust-anstream.git /var/lib/mock/f40-build-2053589-49096/root/chroot_tmpdir/scmroot/rust-anstream
Cloning into '/var/lib/mock/f40-build-2053589-49096/root/chroot_tmpdir/scmroot/rust-anstream'...
$ git fetch origin 6fe4355d273a25986568f3f0b0c87c2911e900e4:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-anstream
 * [new ref]         6fe4355d273a25986568f3f0b0c87c2911e900e4 -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 6fe4355 Update to version 0.6.4; Fixes RHBZ#2241248