Type name:  font

Subtype name:  otf

Required parameters:  None

Optional parameters

   Name: outlines  
   Values: a comma-separated subset of TTF, CFF, and SVG

      This parameter can be used to specify the type of outlines
      provided by the font.  The value "TTF" shall be used when a
      font resource contains glyph outlines in TrueType format, the
      value "CFF" shall be used to identify fonts containing
      PostScript/CFF outlines, and the value SVG shall be used to
      identify fonts that include SVG outlines.  TTF, CFF, or SVG
      outlines can be present in various combinations in the same
      font file; therefore, this optional parameter is a list
      containing one or more items, separated by commas.  Order in
      the list is not significant.

Encoding considerations:  Binary

Interoperability considerations:  As it was noted in the first
   paragraph of RFC 8081's Security Considerations section, a single 
   font file can contain encoding of the same glyphs using several
   different representations, e.g., both TrueType and PostScript
   (CFF) outlines.  Existing font rendering engines may not be able
   to process some of the particular outline formats, and downloading
   a font resource that contains only unsupported glyph data format
   would be futile.  Therefore, it is useful to clearly identify the
   format of the glyph outline data within a font using an optional
   parameter, and allow applications to make decisions about
   downloading a particular font resource sooner.  Similarly, another
   optional parameter identifies the type of text shaping and layout
   mechanism that is provided by a font.

Published specification:  ISO/IEC 14496-22 "Open Font Format" (OFF)
   specification [ISO.14496-22.2015] being developed by ISO/IEC SC29/
   WG11.

Applications that use this media type:  All applications that are
   able to create, edit, or display textual media content.

Additional information:

   Magic number(s):  The TrueType fonts and OFF / OpenType fonts
      containing TrueType outlines should use 0x00010000 as the
      'sfnt' version number.

      The OFF / OpenType fonts containing CFF outlines should use the
      tag 'OTTO' as the 'sfnt' version number.  There is no magic
      number for SVG outlines; these are always accompanied by either
      TrueType or CFF outlines, and thus use the corresponding magic
      number.

   File extension(s):  Font file extensions used for OFF / OpenType
      fonts: .ttf and .otf

      Typically, the .ttf extension is only used for fonts containing
      TrueType outlines, while the .otf extension can be used for any
      OpenType/OFF font, either with TrueType, CFF, or SVG outlines.

   Macintosh file type code(s):  (no code specified)

   Macintosh Universal Type Identifier code:  "public.opentype-font"

   @font-face Format:  opentype

   Fragment Identifiers:  None

Person & email address to contact for further information:  
   Vladimir Levantovsky (vladimir.levantovsky&monotype.com).

Intended usage:  COMMON

Restrictions on usage:  None

Author:  The ISO/IEC 14496-22 "Open Font Format" specification is a
   product of the ISO/IEC JTC1 SC29/WG11.

Change controller:  The ISO/IEC has change control over this
   specification.