src/Tools/VSCode/extension/README.md

 ## Important User Settings ##
 
   * `isabelle.home` points to the main Isabelle directory (ISABELLE_HOME).
   * `isabelle.cygwin_root` (on Windows) points to the Cygwin installation,
     e.g. ISABELLE_HOME/cygwin for a regular Isabelle application bundle.
+
+
+## Isabelle symbols ##
+
+Isabelle symbols like `\<forall>` may be rendered using the extension Prettify
+Symbols Mode. It needs to be configured manually as follows:
+
+ISABELLE_HOME/src/Tools/VSCode/extension/isabelle-symbols.json contains a
+configuration (generated via `isabelle vscode_symbols`). Its content needs to
+be copied carefully into the regular VSCode User Preferences.