Why is the name for uni02C9 firsttonechinese? This is the spacing macron character so is firsttonechinese an error?
Not according to Unicode and SIL.
The unicode name is
MODIFIER LETTER MACRON but the Adobe Glyph Library has it as
firsttonechinese is not Adobe’s recommended name for U+02C9 – note that 02C9 is not in Adobe Glyph List For New Fonts. Rather,
uni02C9 is the recommended name.
If a font uses
firsttonechinese for a glyph, some Adobe sofware will, if needed and no other info is available, assume U+02C9 was the underlying character (see the Adobe Glyph List).
The aglfn defines names for final fonts. And the glyph will get an uni-name on export. We are speaking about design time names.
I need to clarify that previous statement.
In checking the sources again I discovered that I misspoke about SIL. I was referencing a SIL font which had been saved in Glyphs’ file format so had been updated using GlyphData.xml data. That caused my error, along with my inattention to that small file format detail. SIL does not make that recommendation.
As to Unicode, they reference the older Adobe name in their data files, so while technically they don’t make a recommendation, the reference alone would be satisfactory for most designers. As Georg pointed out, the final product will be uni02C9 anyway so should work just fine. The name used by the GlyphData.xml file is just a more descriptive usage name.