> larger load times due to an asinine amount of analytics (tracking) and advertising scripts executing on each page<p>I think most of the extra bandwidth and load times come simply for the large assets use (unoptimized/large/unused images, font files, css files and JS files). Most JS scripts are usually under 100kb, but an unoptimized image can add a few megabytes of extra data.<p>Also, if it's for development, why would it be a browser extension? Most website-testing tools are external (e.g. pingdom page speed test/google pagespeed), as you only want it to use at a specific time on a single website.<p>I am also a big confused, is it a development tool or an ad-blocking tool?