Copy-pasting text from that font yields garbage characters.
The terms typically refer to generic internal labels assigned to missing or unembedded fonts within a PDF document. This often happens when a PDF is created by software that fails to properly embed the original font data or uses a "Character Identifier" (CID) system to map glyphs to a collection rather than using standard font names. Common Issues cid font f1 f2 f3 f4
It is a reminder that our digital reality is fragile. It hangs by a thread of resource maps and embedded subsets. When the map is lost, we do not get chaos—we get the raw, structural truth. Copy-pasting text from that font yields garbage characters