hyperlink to Creative Commons has space, breaking the URL

[bhpayne]

The content of templates/_footer.html is

    <P>
      <small>
        Site content, the project software, and data are covered by the 
<a href="https://creativecommons.org/licenses/by/4.0/">Creative 
Commons Attribution 4.0 International License</a>
      </small>
    </P>

When rendered on http://localhost:5000/list_expressions the text is correct but the URL goes to https://creativecommons.org/licenses/by/4.%200/ which isn't valid.

I don't understand how a space gets inserted after the .