@johncox-google I know this sentence fragment has caught the eye of a few reviewers already.  I would suggest this: Add a translators comment explaining what the "or" is an alternative to, and add a regular comment so that future coders will understand that this is a carefully chosen case, and that it should remain this way:
```
# Developers: this is a sentence fragment, which is usually frowned upon.  The design of the page
# uses this fragment to provide an "else" clause underneath a number of choices.  It's OK to leave it.
# Translators: this is the last choice of a number of choices of how to log in to the site.
${_('or, if you have connected one of these providers, log in below.')}
```