In COLR.closure_glyphs augment the subset with the glyphs rechable from the COLRv1 base glyphs already in the subset. In COLR.subset_glyphs, subset and rebuild LayerV1List and BaseGlyphV1List with the base glyphs to keep. Drop COLR if emptied
In COLR.closure_glyphs augment the subset with the glyphs rechable from the COLRv1 base glyphs already in the subset. In COLR.subset_glyphs, subset and rebuild LayerV1List and BaseGlyphV1List with the base glyphs to keep. Drop COLR if emptied