Feel free to send a pull-request if you have ideas to improve this project, although this is a side project so if it's a large contribution it might be a while before it gets reviewed.
While you're working on the project, the easiest way to test your local changes is to go to chrome://extensions in your chrome browser, turn developer mode on, and load the "src" folder as an unpacked extension. Note that users who have "Show me adult content without checking" off will get a warning page when importing from a mature or explicit work, so if you're changing how metadata is imported you should probably check against both page formats.