Hello!
I have many Unicode codes missing in the Glypho for glyphs name, this is a client job, and he uses a charset-checker to check the missing Glyphs codes and appear many missing codes that are already added to the font file, so there is advice to show those codes.
I use Glyphs 3.2 (3186)
I have attached a comparison between the current font file and a previous file.
I believe this is mostly because the “missing” Unicode code points are for presentation-style glyphs. Since these glyphs are accessed using OpenType features and not typed directly, they are often not encoded. For example, you would type ل (U+0664) and not ﻠ (U+FEE0), and the medi-glyph get automatically chosen based on context: للل (three U+0664).
The question is whether this is a problem. If you absolutely need these Unicode code points, add a Use Arabic Presentation Form Unicodes custom parameter as described in the topic linked above.