Gecko allows syntax like matrix(1, 0, 0, 1, 5em, 10%), with <translation-value> instead of <number> for the last two entries (it also accepts <number>). Likewise for matrix3d(), it allows <translation-value> instead of <number> for the fourth- and third-to-last entries, and <length> instead of <number> for the second-to-last. The spec doesn't allow this, but some Gecko developers want it to:
(David Baron [:dbaron])
> We should change this in the same release that we unprefix. (Though I think
> maybe we should try to convince other browsers to change.)
(Matt Woodrow (:mattwoodrow))
> This was definitely an intentional choice to provide flexibility for
> authors, consistency with the translate() functions, and consistency with
> our existing matrix() implementation.
> I'd prefer to see this allowed in the spec than remove it from our code.
Currently, the other three engines (IE, WebKit, Opera) don't allow this, but it seems like a possibly useful feature. Do we want Gecko to remove the feature, or everyone else to add it? Are other engines interested in adding it?
Paris F2F meeting resolved to not change the spec in this regard.
Then it's WONTFIX, right?