On https://wltools.github.io/LanguageSpec/ there are three in a row in the Table of Contents under Language Specification -> Resources for Implementers -> General Advice For Implementers:
Also http://visx.io/ and packagedata.net may be relevant (though inclusion of lists of libraries like packagedata.net may be orthogonal and thus a nongoal/distraction from the purpose of this site).
While browsing the site (very impressive, sad I only just found it) I found some of the READMEs have dead links. In particular On https://wltools.github.io/LanguageSpec/Specification/Syntax/ the
List of all operators with precedence, associativity, affix, and arity
link should be https://wltools.github.io/LanguageSpec/Specification/Syntax/OperatorTable/.On https://wltools.github.io/LanguageSpec/ there are three in a row in the Table of Contents under Language Specification -> Resources for Implementers -> General Advice For Implementers:
Exploring Mathematica
link should be to https://wltools.github.io/LanguageSpec/Resources/Exploring-Mathematica/List of Independent Wolfram Language Projects
link should be to https://wltools.github.io/LanguageSpec/Resources/List-of-W-Language-Projects/Software Development Tools for Wolfram Language
link should be to https://wltools.github.io/LanguageSpec/Resources/ProgrammingTools/Also http://visx.io/ and packagedata.net may be relevant (though inclusion of lists of libraries like packagedata.net may be orthogonal and thus a nongoal/distraction from the purpose of this site).