1. Does Serbian has to be registered with the languagesystem statement "languagesystem cyrl SRB"? I found a font, in which it seems to be registered with "languagesystem latn SRB".
2. If I want to exclude a script from a feature, it seems, that I cannot write "script cyrl exclude_dflt" for example. At least this is not defined in the OpenType Feature File Specification. Or is "script cyrl" equivalent to "script cyrl exclude_dflt"? (If yes, this would be a bit inconsistent, because "language DEU" is equivalent to "language DEU include_dflt".)