[bug-libunistring] Unicode security specifications

[Bruno Haible]

Hi Simon,

The Unicode 15.1.0 announcement [1] says:
  "Security-related updates have been made to
     UAX #9, Unicode Bidirectional Algorithm
   and
     UAX #31, Unicode Identifiers and Syntax
   along with updates to
     UTS #39, Unicode Security Mechanisms.
   These updates complement the release of a new Unicode Technical Standard,
     UTS #55, Unicode Source Code Handling."

Do you have a feeling on the importance of these specifications?
Which types of applications could make use of them, and for which
applications are they mandatory or highly recommended?

      Bruno

[1] http://blog.unicode.org/2023/09/announcing-unicode-standard-version-151.html