Wow, I didn't know that! I thought the tracking protection was just about the DNT header and I didn't expect that to make much difference here. However, even disabling that, I only get ~200 requests. There's still a lot missing... is it still blocking things under the hood?

It may also be that different resources are loaded based on browser agent to track the user in different ways/display the page correctly on different browsers/polyfill javascript differences