$ git clone -n https://src.fedoraproject.org/rpms/rust-bytestring.git /var/lib/mock/f38-build-side-43-rust-devel-1411766-31436/root/chroot_tmpdir/scmroot/rust-bytestring
Cloning into '/var/lib/mock/f38-build-side-43-rust-devel-1411766-31436/root/chroot_tmpdir/scmroot/rust-bytestring'...
$ git fetch origin d29a3c1dff68fa0081a6026d166cc0ef8608a47d:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-bytestring
 * [new ref]         d29a3c1dff68fa0081a6026d166cc0ef8608a47d -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at d29a3c1 Update to version 1.3.0; Fixes RHBZ#2175337