$ scap prep 1.36.0-wmf.3
...
3:57:16 Fetching core to /srv/mediawiki-staging/php-1.36.0-wmf.3
23:59:42 Checkout wmf/1.36.0-wmf.3 in
/srv/mediawiki-staging/php-1.36.0-wmf.3
23:59:42 Unhandled error:
Traceback (most recent call last):
 File "/usr/lib/python2.7/dist-packages/scap/cli.py", line 341, in run
   exit_status = app.main(app.extra_arguments)
 File "/srv/mediawiki-staging/scap/plugins/prep.py", line 143, in main
   git.checkout(dest_dir, checkout_version)
 File "/usr/lib/python2.7/dist-packages/scap/git.py", line 393, in checkout
   git.checkout('--force', '--quiet', rev)
 File "/usr/lib/python2.7/dist-packages/scap/sh.py", line 1428, in __call__
   return RunningCommand(cmd, call_args, stdin, stdout, stderr)
 File "/usr/lib/python2.7/dist-packages/scap/sh.py", line 775, in __init__
   self.wait()
 File "/usr/lib/python2.7/dist-packages/scap/sh.py", line 793, in wait
   self.handle_command_exit_code(exit_code)
 File "/usr/lib/python2.7/dist-packages/scap/sh.py", line 816, in
handle_command_exit_code
   raise exc
ErrorReturnCode_1:

 RAN: /usr/bin/git checkout --force --quiet wmf/1.36.0-wmf.3

 STDOUT:


 STDERR:
error: pathspec 'wmf/1.36.0-wmf.3' did not match any file(s) known to git

23:59:42 prep failed: <ErrorReturnCode_1>

 RAN: /usr/bin/git checkout --force --quiet wmf/1.36.0-wmf.3

 STDOUT:


 STDERR:
error: pathspec 'wmf/1.36.0-wmf.3' did not match any file(s) known to git