Hello Fabian and James,
Thank you for looking into this.
I remark that the symbolic links created in the "X11/Type1" folder change the file extension of the original file. In particular:
> file /usr/share/fonts/X11/Type1/NimbusSans-BoldItalic.pfb
/usr/share/fonts/X11/Type1/NimbusSans-BoldItalic.pfb: symbolic link to ../../type1/urw-base35/NimbusSans-BoldItalic.t1
(Notice the origin file has extension "t1" but the symbolic link changes that to "pfb")
Is this change intentional?
It appears pdfbox is using the extension to determine the file type because renaming the symbolic link to preserve the "t1" extension in the symbolic link fixes the problem.
Fabian mentioned that "upstream has decided to rename the binary font files and in that course change the file extensions from .pfb to .t1." but from the above experiment it seems that upstream changed the actual file format, and then they changed the file extensions to match the new format.
IMHO opinion, the solution would be to either not create the symbolic links or to preserve the original names including the extension. I don't know enough to know what is best.