The "Function List" window is a window used for quick navigation in your script. When double-clicking on one of the function listed in the window (if there is any), it will bring you directly to the declaration line. Behind this window, LuaEdit uses Exuberant CTags to scan function tokens and display the results in that window. The .tag files generated by Exuberant CTags are temporarely stored in the temporary folder specified in the "General Tab" of LuaEdit's settings window.