In a message to Junichi Uekawa 
Jason Rothstein  wrote:

 JR>   FTS-* are the mandatory ones, FSC-* are the optional ones.

Not quite.  FTS documents are official FidoNet Technical Standards that
have been approved by the FTSC, however that does not mean they are
necessarily mandatory.  FSC documents are standards proposals and
miscellaneous documents.  See FTSCLIST.069 for a list of FTS and FSC
documents.

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