With a chrome extension such as Resource Override (or a similar extension for any browser) we can override any JS file with our own modified version for reverse engineering of the website, except I just encountered one where the URL of the javascript I want to manipulate is data:text/javascript;charset=UTF-8;base64,DQoNCi ... snip ...
The Resource Override extension won't seem to replace this file, perhaps because it's looking for network requests, and this file is (I think) something generated dynamically, not loaded over the network. How can I override such a resource in Chrome?