Should we spec required prefixes directly in the relevant specs? #247

Consensus is that the following specs should link to Compat, because they have features mentioned in there:

• Snapshot
• Animations
• Media Queries
• Images
• Alignment
• Transforms
• Backgrounds & Borders
• UI
• Flexbox
• Filters
• Masking
• Transitions
• Size Adjust

Some features have de-facto required prefixes. This is currently specified in the Compat Spec, maintained in WHATWG. Should we instead be specifying these directly in the spec?

My (possibly biased) reading of the issue:

Pro:

• keeps CSS features specced in CSS specs, rather than relying on an external standards body
• puts definitions of required features near the features they're related to, rather than in a completely separate spec - we purposely don't use errata specs for anything else!
• admits that these are, indeed, required parts of the web platform, even if they're distasteful

Cons:

• they're ugly I guess?