It is like @CanIUse but for the browser devtools, created & curated by @pankajparashar. Get weekly tips & tricks for your favorite browser devtools by subscribing to the newsletter!
Open Command Menu using Cmd+Shift+P or Ctrl+Shift+P. Search for "Show Coverage" and press Enter. (this will open the Coverage drawer next to the Console).
Click the "Reload" button to see the unused JavaScript bytes per file. Clicking the row, will open the file in the Sources panel highlighting the unused lines with red colour.