At end of my response to Antoine Leca, I suggested something which may merit some comments:
> What is clear is that there's no way to enable these features explicitly in plain-text files, if there's no standard format control in Unicode to enable these OpenType font features. May be these could become new "characters" to allocate in plane 14? What I mean here is that there's currently no defined way to convey in plain text files the intended rendering "features" that are now common in OpenType fonts and engines. What we currently have is the script identification and the language identification with language tags in plane 14, but languages tags reaveal much useless, unlike the feature tags that we currently cannot encode. Is there some pending proposal to encode a new set of FEATURE TAGs, in the same spirit as LANGUAGE TAGs in plane 14? Or to use a new leading character in the LANGUAGE TAGs block to mark the begining of a feature tag instead of a language tag (this would require only 1 codepoint allocation, for example E0002)? It would find an immediate application within OpenType renderers, which could be instructed to set or unset some rendering features found today in common fonts, and that could be transported in plain text files, rather than only in rich-text file formats like XML-based documents or Word documents or CSS stylesheets (if such possibility gets added and standardized into CSS).
