The specification on page 304 lists both A_ONE and A_ZERO as default modes. This looks like a cut&paste error.
A_ONE is the default.
The WebGL specification does not have page numbers (it's HTML); if it did, it does not have enough material to come anywhere near needing a page 304. Also it does it mention A_ONE or A_ZERO.
It seems clear this bug was miscategorized as WebGL instead of COLLADA.
(In reply to comment #3)
> It seems clear this bug was miscategorized as WebGL instead of COLLADA.