Comment 6 for bug 1054204

In broad terms there is the simple metadata (fontname + boolean for italic + boolean for bold); and there is the complex metadata (name, family name, numerical slant, numerical weight, …). Various applications; including FontConfig IIRC makes errornous presumptions when mixing those.

Now, from a UFF PoV, we may have to change the mapping method to cope with certain software like MSIE; but that would none-the-less still leave the handling of "separate" metadatas broken. The only string that is /supposed/ to be globally unique is the Postscript Name; which OpenType and CSS mandate, and which Fontconfig currently junks:

  https://bugs.freedesktop.org/show_bug.cgi?format=multiple&id=38737

Adding that to FontConfig as an available matching spec would at least allow debugging by canonically knowing what you're getting.