Happy to address this. Honestly, I'm not sure why Firefox gives that rather scary warning. It could be because LB uses a content script to display the countdown timer and warning message within the tab, over the web page. (Content scripts can, in principle, access all data on the web pages you view.) It could be because LB requests 'tabs' permission, so it can intermittently check whether block conditions are met for all open tabs, not just the active tab. I'll look into it. In any event, all the source code is publicly available on GitHub, so you can check that LB isn't doing anything untoward!