Document (and then ensure) feature parity with CLI

[jmandel]

From chat discussions, the portal is being used by non-technical end-users as part of go-live procedures. It'd be good for us to have a full understanding of any tests that don't get surfaced in the portal, and then we can evaluate whether/how to close the gap.

One specific question that came up is whether CORS checks are performed

Can start with just a bullet list here if this makes sense to you @ljoy913