Re: [webauthn] truncation to 64-byte upper limit doesn't mention character boundaries

If you go with normative language, I would prefer this:

> Authenticators MUST perform any UTF-8 encoded string truncation on a code point boundary, and are encouraged perform such a truncation on a extended grapheme cluster (EGC) boundary [[!UAX29]]. 

... in place of SHOULD/MAY as in the proposal. I used non-normative language about EGC because SHOULD is too strong a recommendation. MAY might be appropriate instead.

Note that a mid-code-point truncated string makes file formats such as JSON invalid (unless a transfer encoding such as base64 is applied to the name--which I think is beside the point??)

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Received on Wednesday, 18 July 2018 19:05:40 UTC