$ git clone -n https://src.fedoraproject.org/rpms/rust-serde_with_macros.git /var/lib/mock/f40-build-2367694-60387/root/chroot_tmpdir/scmroot/rust-serde_with_macros
Cloning into '/var/lib/mock/f40-build-2367694-60387/root/chroot_tmpdir/scmroot/rust-serde_with_macros'...
$ git fetch origin 854354ac1e5fcffbe135627a76991fa4c2f61fcb:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-serde_with_macros
 * [new ref]         854354ac1e5fcffbe135627a76991fa4c2f61fcb -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 854354a Update to version 3.5.1; Fixes RHBZ#2259380