No specific info about version 3.1. Please visit the main page of SF Symbols on Mac Informer.
Noun Project is a visual language that anyone can use and understand.
Select among a wide range of characters and symbols.
It transcribes characters in keyboard mode into the HTML mode.
Detexify lets you draw math symbols to find the corresponding LaTeX command.
PascalGladiator is a free graphical IDE for FPC and debugger front-end for GDB.