I know about Workspaces recently introduced in DevTools but that is not that i need. For example: page uses jquery that is loaded from CDN, i modify jquery library code, pre
You could try it this way (for jquery):
-load the page first time and on the sources tab put a breakpoint on line number 1 -then reload the page modify the file and save ( you can see that the page has paused due to the breakpoint ) -press the play button and the page will start to load. The modifications you made will work. The downside of this solution is that once you refresh again the page, the modifications will be lost.
Hope that helps!