The IETF is noting the progress of an updated draft: Formal SignWriting draft-slevinski-formal-signwriting-04 https://tools.ietf.org/html/draft-slevinski-formal-signwriting-04.html
which continues to describe an implementation of SignWriting in the as-yet unassigned Plane 4, including a detailed breakdown of blocks for different types of characters. I know the struggle between Slevinski and Unicode is long and contentious, with Slevinski arguing for years that the Unicode encoding of SignWriting is useless because it doesn't encode position, and vowing that no implementation (under his aegis) will ever use it). Nevertheless, I wonder if it would be appropriate for Unicode or WG2, in some capacity, to protest in some formal way against this recommendation to arrogate an unassigned plane instead of using the PUA, which is the correct place for unassigned characters. -- Doug Ewell | Thornton, CO, US | ewellic.org