In Ghostscript’s source file gs_cidfn.ps , you will find:
PDF repair tools sometimes report: /F1 – Invalid CIDSystemInfo – forcing to /Normal /Fixed cidfont f1 normal fixed
: Preflight checks in professional software like Adobe Acrobat may report "CIDFont+F1 contains bad/widths," leading to poor print quality even if the document looks fine on screen. In Ghostscript’s source file gs_cidfn