Lists the number of lines you have in your functions with a detailed breakdown on which commands you've used.
You can either run it without any arguments (e.g. through a doubleclick) to search through the folder (and its subfolders) the analyser located in or by giving the path as an argument when running it from the console.
Example: .\FunctionAnalyser.exe C:\Users\<username>\AppData\Roaming\.minecraft\saves\world\datapacks