When tabbing through the header on a regular page, each of the tabs reacts to focus using the browser default behaviour (on Mac this is often a blue outline).
When making it to the watch star, however, it's gone (there is a very subtle color change inside the star, but that's too subtle for focus, it's barely enough for hover).
There doesn't seem to be any reason for this (it's not explicitly removed from :focus, just from the element in general and :focus inherits it).
Fro the commit history, looks like this was added way back to deal with image outlines, but this has been refactored since and just forgotten.
Version: 1.18.x
Severity: normal