> > and UAs like Firefox make the efforts to change the order when it's not
> > necessary
> You're confusing "make efforts to change the order" and "don't make
> efforts to preserve the order".
> Let's take a simple example: background. Internally this is stored as
> values for background-position, background-image, etc, with no
> particular ordering imposed on them (they're just members of a struct).
> The original string is not stored anywhere, since it's not needed for
> normal operation and would take up extra memory. When asked for
> .background, Gecko just serializes this unordered representation, which
> implies picking an arbitrary order at that point.
What I meant with "make efforts to change the order" was, that it was working different in earlier versions of Firefox. I.e. somebody must have changed the serialization code so that the order we previously had in Firefox has now changed.