In the context of PDFs and PostScript printing, labels like , etc., are internal font object references . They are essentially placeholders used by the software to keep track of different fonts used within a specific document.
The "F1, F2" labels are just internal shorthand for the first, second, or third font used in that specific document. Why You Can't "Download" These Fonts cid font f1 f2 f3 f4 f5 f6 f7 fonts free verified download
The font CIDFont+F1 is Arial (blod) and CIDFont+F2 is Arial (Regular) CID+ Fonts - Adobe Community In the context of PDFs and PostScript printing,