Lisp reader syntax and bootstrap (was: Re: Disambiguate modeline character for UTF-8?)

[Ulrich Mueller]

>>>>> On Sat, 08 Jul 2023, Eli Zaretskii wrote:

>> Thanks, but I think it's too early in the build to use \N{name} syntax:

> Thanks, I've somehow missed that.

I had done my tests if a non-ASCII char is displayed correctly with ?У.
This including building Emacs from scratch. I changed from ?У to
?\N{name} last minute and apparently tested only if the file can be
loaded and byte-compiled, but not a full bootstrap. :( Sorry for that.

Are there any other features of lisp reader syntax where one must be
careful? Maybe the Elisp Reference Manual should warn about this?