Advisory Report: "CIDFont F1–F5" Identification and Security Risks
Example CSS snippet:
Instead of searching for a download, try these proven workarounds found on the Adobe Community and Superuser forums: CID+ Fonts - Adobe Community
Use the Preflight tool: Go to Tools > Print Production > Preflight.
In Adobe Acrobat, go to File > Properties > Fonts to see if the real font name is listed next to the "F" placeholder.