Clarification: using dynamic/generated `src` values

[hybridherbst]

It seems that neither the spec nor the explainer referenced from the Readme mention what should happen when the source data is in memory, for example created from URL.createObjectUrl(someBlob). Images, audio, video work that way; however it looks like at least the current implementation on Safari does not accept such URLs, which may or not may be a bug given that the spec doesn't explain it.

Or maybe it doesn't need to because that's how resources on the web work?

[zachernuk]

Safari's implementations are presented as "testable" feature previews but it's definitely expected that blob-loaded assets should function.

Looking through other specifications I haven't found any explicit language around the support for blobs in <img> or <video>, where I've definitely used them before. I'm happy to add language where it's typical, but I would hope this just works! (I'm mainly testing in visionOS 2, other implementations are more speculative)