What does your feature entail? What is it for? How will it affect existing workflows or user experience?
Currently, extensions cannot access local files on the disk, nor run on file:// URLs. This prevents users from using, for example, userscripts on local files.
Chrome (and other chromium browsers) have a toggle when managing the extension, called "Allow access to file URLs". For example:
What are the exact ways that you see a user using your proposed feature? Please go into as much detail as possible, and provide examples of how other browsers/apps implement this feature, if applicable. If your feature suggestion adds on to an existing feature, how would it work into it to extend its usefulness?
Users will be able to load userscripts locally and develop them on a separate code editor, using this tutorial.
Users will also be able to run these userscripts on local files.