The introduction to the sections on set and animate has been changed to refer to "styling attributes", but the content model does not reflect that. Although this is syntactically correct (since attributes in other namespaces are excluded from the content model and pruned prior to validation) we can do something more useful: I propose adding a comment to the content model highlighting that styling attributes in other namespaces are also considered for processing in the animation semantic, even though they are excluded from the content model from a formal specification perspective.
[snip] however, point (1) is a wider problem, since there are 13 instances of {any attributes in TT Style Namespaces} in various content models that need to be dealt with as a whole. I suggest opening another issue for point (1), with the suggestion to change these to read {any styling attribute} or {any animatable styling attribute} depending on the context (the latter for animate and set, the former for the 11 other cases.
Extracted from #1153:
As per https://github.com/w3c/ttml2/pull/1154#discussion_r321253150 where @skynavga wrote: