[mediaqueries-5] image backgrounds vs transparency

Given the name of prefers-reduced-transparency, I would expect it to be "transparency is bad, but complex backgrounds are totally fine". However, I wanted to check if that's actually a correct interpretation of the accessibility requirement.

(@cookiecrook mentioned that prefers-reduced-transparency derives from a MacOS setting in a context where transparency is often used but background images aren't a thing; but on the Web, they definitely are. So we have this additional thing to consider.)

So the question is, is the requirement that generated prefers-reduced-transparency really about wanting reduced transparency e.g. because of some confusion over whether the obscured content is still relevant, or is it also about reducing decorative visual complexity--including both the use of transparency but also complex background images, such that authors should not be using complex opaque backgrounds either?

If the former (really only about transparency), do we also need an MQ for reducing e.g. patterned or image backgrounds to more subtle or solid effects? (And if so should that really be a separate MQ, given that adding one adds authoring complexity and fingerprinting surface?)

No file or test is named. Start by reviewing the current prefers-reduced-transparency requirement and the issue discussion about image backgrounds, opaque backgrounds, and fingerprinting; done means the CSS Working Group records whether the existing media feature covers this case or whether a separate feature is needed.