For Mac: ⌘ P to search for sources ⌘ ⇧ F to find in files
! Search for the string across all files. @ Search for function definitions, across all files, containing the string. file.js:12 Open "file.js" and go to line 12 mod#onLoad Find the string "onLoad" in all files containing "mod" in their name.
Pop open Firefox's developer tools (Ctrl + Shift + I in Windows) and head to the tools' settings (gear icon). There's an option in there to disable the browser's cache while you've got the tools open.
Hit F7 to turn off the Caret browsing mode.