Browser Support • Way to block preload in PM 33.1

Additionally, turning preload off on some of these could break code, if it's poorly written

A page to test on would be helpful.

I think https://ruffle.rs/ is one of the badly-written sites that causes issues with this, with menu choices at the top just hanging for a minute without preloading.
Pretty sure that was still not working well in 33.0.2 but seems to work OK now.

---