Browser extensions are useful because they bring additional functionality to your web browser, allowing you to do things like track price histories for online products, change CSS styling on certain pages, and, of course, block ads and other scripts that get in the way. Well, browser extensions aren’t always coded well. Depending on what they do, they might have to run various types of analyses and/or make changes to a page before it loads — and if an extension isn’t coded well, all of that processing can slow things to a crawl. That’s why Microsoft is currently testing an upcoming feature in …