Requirements flags in reference files

Hey Peter & Gérard,

I've seen Gérard remove these flags in the past [1], but the guidelines [2] are somewhat ambiguous. Should a ref file not have flags? For cases where the test and the reference have the same flag (for example, ahem), it makes sense that you needn't duplicate the info in the ref file as its bound to the test.  What about cases where the ref file has a flag that the test file does not? An example off the top of my head is maybe using SVG to render something equivalent that you're testing in CSS.

And more generally, how exactly are these flags used?  I saw some confusion about flags at TestTWF Tokyo as well that raises this question for me.

(cc'ing my colleague Bem, who's not subscribed to this list, but who's encountering this situation)

Thanks,
-Rebecca

[1] http://hg.csswg.org/test/rev/ed3f96bded71
[2] http://wiki.csswg.org/test/format#requirement-flags