This interface is the type signature that is expected to be present on any attribute key that contributes to the determination of what font to use to render some text.

  This interface is the type signature that is expected
to be present on any attribute key that contributes to
the determination of what font to use to render some
text. This is not considered to be a closed set, the
definition can change across version of the platform and can
be amended by additional user added entries that
correspond to logical settings that are specific to
some type of content.