Definitions of blocks

[Paul Hoffman]

draft-ietf-idnabis-tables-06.txt says:

2.4.  IgnorableBlocks (D)

   D: Block(cp) is in {Combining Diacritical Marks for Symbols,
                       Musical Symbols, Ancient Greek Musical Notation}

   This category is used to identifying code points that are not useful
   in mnemonics or that are otherwise impractical for IDN use.  In
   general, these code points are not suitable for use for IDN.

Are those blocks defined anywhere? Or is an implementer meant to figure them out on his/her own?