$ git clone -n https://src.fedoraproject.org/rpms/rust-proc-macro-hack.git /var/lib/mock/f38-build-side-43-rust-devel-1415765-31455/root/chroot_tmpdir/scmroot/rust-proc-macro-hack
Cloning into '/var/lib/mock/f38-build-side-43-rust-devel-1415765-31455/root/chroot_tmpdir/scmroot/rust-proc-macro-hack'...
$ git fetch origin 14e1f637544033c9a7816f2a06818595ce4bcc0b:KOJI_FETCH_HEAD
From https://src.fedoraproject.org/rpms/rust-proc-macro-hack
 * [new ref]         14e1f637544033c9a7816f2a06818595ce4bcc0b -> KOJI_FETCH_HEAD
$ git reset --hard KOJI_FETCH_HEAD
HEAD is now at 14e1f63 Update to version 0.5.20+deprecated; Fixes RHBZ#2155059