[css3-transforms] Should rotate3d be listed as a primitive?

Rotate3d is not listed as transform function primitive at
http://dev.w3.org/csswg/css3-transforms/#transform-primitives, yet rotate3d(1,
1, 1, 0) is provided as an example of an identity transform function at
http://dev.w3.org/csswg/css3-transforms/#TermIdentityTransformFunction
Should rotate3d be a primitive?

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Best Regards,
David Zbarsky