Analyse following RPM build log snippet. Describe contents accurately, without speculation or suggestions for resolution.            
Your analysis must be as concise as possible, while keeping relevant information intact.
Snippet: 
Error: Invalid value for '[PATH_OR_URL]': Cmd('git') failed due to: exit code(128)
  cmdline: git fetch -v -- origin +refs/pull/37301/head:refs/remotes/origin/pr-changes/37301
  stderr: 'fatal: couldn't find remote ref refs/pull/37301/head'
This seems like Packit wasn't able to clone PR HEAD