PFR

[5] Dynamic HTML in Communicator, 2024-08-16T08:58:05.000Z, 2000-12-06T09:39:09.036Z https://web.archive.org/web/20001206092700/http://developer.netscape.com/docs/manuals/communicator/dynhtml/webfont1.htm#1032362

[1] Re: Font MIME types (Chris Lilley 著, 2015-04-23 02:07:48 +09:00 版) https://lists.w3.org/Archives/Public/www-style/2015Apr/0335.html

TrueDoc Portable Font Resource was implemented in a browser (in Netscape 4) but is no longer relevant; with the move from closed-source Netscape to open-source Mozilla that format, which required payment of license fees to Bitstream, was dropped.

[2] RFC 3073 - Portable Font Resource (PFR) - application/font-tdpfr MIME Sub-type Registration (2015-03-22 18:04:48 +09:00 版) https://tools.ietf.org/html/rfc3073

[3] RFC 3073 - Portable Font Resource (PFR) - application/font-tdpfr MIME Sub-type Registration (2015-03-22 18:04:48 +09:00 版) https://tools.ietf.org/html/rfc3073

The PFR media type has been previously registered with IANA as
application/vnd.truedoc. In view of its subsequent widespread
adoption as a standard font format by multiple standards bodies who
have relationships with the Internet community, Bitstream has been
asked to re-register this media type within the IETF tree.

[4] TrueDoc - Bitstream (2015-04-24 12:15:24 +09:00 版) http://web.archive.org/web/20040603123430/http://www.bitstream.com/categories/developer/truedoc/pfrspec.html