Crater errors aren't entirely helpful

I don't know whether this is a user error or if I should Do Something to fix it:

```shell
Bad URL: failed to parse URL: RelativeUrlWithoutBase: relative URL without a base
command failed: 'Cloning into './font_repos/Alegreya'...
fatal: could not read Username for 'https://github.com': terminal prompts disabled
'
command failed: 'Cloning into './font_repos/elsiefont (404)'...
fatal: unable to access 'https://github.com/googlefonts/elsiefont (404)/': URL rejected: Malformed input to a URL function
'
command failed: 'Cloning into './font_repos/glory'...
fatal: could not read Username for 'https://github.com': terminal prompts disabled
'
command failed: 'Cloning into './font_repos/manrope'...
fatal: could not read Username for 'https://github.com': terminal prompts disabled
'
command failed: 'Cloning into './font_repos/Orelega'...
fatal: could not read Username for 'https://github.com': terminal prompts disabled
```

My local cache dir seems well populated so maybe these are just bad sources...?