Followup: It seems Firefox is indeed able to use the matrix part of XYZ LUT with (swapped or not) matrix profiles created with Argyll CMS (just tested, FF 3.6.3, Win7). I think in the case of the profile not being used, it can be related to this bug, atleast under Windows (heh, I opened that myself about two months ago, must've forgot about it):
ICC display profile is not used under Windows if its filename contains Unicode characters
https://bugzilla.mozilla.org/show_bug.cgi?id=560652 Am 12.06.2010 23:16, schrieb Florian Höch:
Hi,The Windows 7 "Photo Viewer" application uses only the matrix part and shows RGB shifted to GRB, while the Windows 7 file manager ("Explorer") uses the LUT part to colour manage its JPEG previews, so those are shown with correct colours, as do other applications that invoke/use the Windows CMM.The Windows 7 explorer thumbnails definitely aren't using the display's associated profile. My guess is that they are colormanaged, but probably with a default internal destination profile (sRGB? On my wide-gamut TFT the thumbnails look overly saturated). Maybe Firefox is doing something similar, ie. silently defaulting to sRGB as destination profile if it can't cope with the display profile?
-- Florian Höch http://hoech.net