History of the "LATIN SMALL LETTER SHARP S" exception

[Alexander Mayrhofer]

Hello,

I'm preparing a presentation regarding IDNA updates. I've tried to find
out the history of the "LATIN SMALL LETTER SHARP S" exception
(unfortunately i missed the stockholm idnabis session). If i understand
it correctly, the codepoint would be Unstable without that exception.

I've found a few messages regarding this, but didn't find the message
documenting the inclusion of the exception.

Could someone point me to the relevant discussion, or a record of the WG
concensus in minutes? 

Thanks,

Alex