I am trying to find the unused methods using the Query Editor in Developer Console.
I have checked Use Tooling API.
Running SOQL like below:
SELECT Id FROM SymbolTable WHERE externalReferences = NULL
But getting this error:
SELECT Id FROM SymbolTable WHERE externalReferences ^ ERROR at Row:1:Column:16 sObject type 'SymbolTable' is not supported. If you are attempting to use a custom object, be sure to append the '__c' after the entity name. Please reference your WSDL or the describe call for the appropriate names.
What I am missing here?