BaseURL is not specified correctly for CSS module scripts

What is the issue with the HTML Standard?

When constructing a CSS module script, Step 5 of the specification says "Let sheet be the result of running the steps to create a constructed CSSStyleSheet with an empty dictionary as the argument." and Step 2 of that specification says "Set sheet’s location to the base URL of the associated Document for the current global object.", but there's a web-platform test that checks that the BaseURL is the URI of the module script, not the document. The test was added here: https://github.com/web-platform-tests/wpt/pull/29408.

I ran into this while implementing CSS module scripts in Firefox (See https://bugzilla.mozilla.org/show_bug.cgi?id=1720570). I've implemented the behaviour that makes the test pass, but that doesn't seem correct according to the specification. I think in this case it makes sense to update the specification to match the test behaviour.

Read the HTML Standard's creating a CSS module script steps alongside CSSOM's create a constructed CSSStyleSheet steps. Run or inspect web-platform-tests/html/semantics/scripting-1/the-script-element/css-module/relative-urls.html and compare its expected module-script base URL with the specification. Done means the specification and test agree on the stylesheet location base URL.