User Agent: Mozilla/5.0 (Windows NT 10.0; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0 Build ID: 20150812163655 Steps to reproduce: I used a local development server (AKA 127.0.0.1) with Disable Cache enabled in developer tools. Actual results: JavaScript was being cached in offline mode with the developer console/inspector open. Expected results: The Disable Cache setting should not be overridden by browser.cache.offline.enabled and prevent caching when the developer console/inspector is open. Refreshes on a local dev server should have fetched new JS from the disk instead of using previously cached files.

Are you sure it is being overridden? For me it's not working even with browser.cache.offline.disabled I am having problems with videos being cached, I haven't tested javascript. Take a look at this bug, it seems the ignore cache option is broken for many people regardless of browser.cache.offline https://bugzilla.mozilla.org/show_bug.cgi?id=1129806