List of all symbols provided by a font

[tie-ling]

In Appendix B, Version 1.6 [January 2, 2021], you mentioned that

I have not found any document or web page that collects them all.

As a math student, some symbols that I need are missing from the table included in this book.

However, as written in contextgarden article, you can get a full list of all symbols supported by the font by using

\setuppapersize[A4]
% font selection. stixtwo has more than 2000~ symbols, while TeX Gyre has about 1500~
% http://mirrors.ctan.org/macros/unicodetex/latex/unicode-math/unimath-symbols.pdf
\setupbodyfont[stixtwo]
\usemodule[fnt-25]
\starttext
\showmathfontcharacters
\stoptext

Results are
times-context-symb.pdf for TeX Gyre Termes,
stixtwo-context-symb.pdf for STIX Two,
context-symb.pdf for Latin Modern.

Some names differ from unicode-math & LaTeX and ConTeXt: \coloneq is named \colonequals.

I think it would be helpful to add this information in your book.