I started trying to nail down exactly what needs to be done to implement URL constraints. Some of it's straightforward (add this field, here's how to handle it in various circumstances), and some of it is not (how do I check whether a candidate matches a URL constraint? I'm almost tempted to translate the link field into an ExplicitRequirement, which... might actually make the most sene. That's not a judgment call I feel comfortable making at midnight.)
I wrote another test as future-proofing, because I noticed a potential issue, given planned changes to the code.
Speaking of changes to the code, I probably should have pulled and rebased before I started making changes, even if those changes are just taking notes on what needs to happen. Oh well, I'll try to remember to do it tomorrow. I can muddle my way into a good state one way or another.
Anyway, I have to wrap up several minutes ago.