According to the docs, there should be a Dynamic Links domain for my project, which is displayed at the top of the Dynamic Links page. The docs have a screen capture like so:
Location of domain according to the Firebase documentation
However, on the Dynamic Links page for my project there is no such domain, at least not one I can see. Here is a screen shot (I've blacked out identifying info, there was no domain under the black square or circle!):
Screen shot of Dynamic Links page with no domain displayed
I've tried looking through settings and options in case there was some kind of toggle, but haven't found anything relevant.