The exact mapping varies by software. Some PDFs define F1 as a Chinese font, others as Japanese. The key is to have a suite of standard CID fonts installed.
If you need a broad library of fonts to fix these "F-tag" errors, use these reputable repositories: cid font f1 f2 f3 f4 f5 f6 f7 fonts free download link
Because they are "internal" labels, there is no single download link that will fix the problem. Instead, you need to identify the The exact mapping varies by software
