Not exporting vs missing

Is there any difference in behaviour when exporting between not having a shape in the character set and having it but with the export box unchecked? I know that Glyphs creates a zero width space character when it’s missing in the set, but I’ve recently noticed that having it set to not export, bypasses that and the final font has no space character in it. It makes me wonder if this is triggered by any other shape too.

No. Except that you can use it as a component in a different glyph if it exists.

Yes, that’s what I’ve always assumed, till I noticed what happens with the space glyph. Is there a reason for that?

A font must have .notdef and space. Even if you do not have them in your exporting set, Glyphs will add them.

That is not making a new space when it is set to not export is a bug. But I’m inclined to leave it like this. Maybe there is a reason to not include a “space”?

Yes, I was just wondering why the different outcome if the space doesn’t exist or if it’s set to not export, since the space glyphs is required. As Georg explained, it’s a bug. My original question was to clarify if this happens with any other glyph, or just the space one. Can I safely assume that no other unnecessary data is stored anywhere when I set shapes to not export?