– stick to official sources like GitHub, Google Fonts, or Adobe’s open‑source releases.
Based on Adobe’s CID specification, the standard mapping is as follows: CID font F1 F2 F3 F4 F5 F6 F7 Fonts Free Download
When a PDF is created and the original font cannot be embedded (or is deliberately omitted to save space), the system substitutes a "base font" and tags it with a simple label like /F1 , /F2 , etc. These are sometimes referred to as or font dictionary keys. – stick to official sources like GitHub, Google