Just today, I am getting CORS errors in Firefox when the Rust book tries to load the FontAwesome fonts. So icons at the top of the page, the left and right angle brackets at the sides of the page, and icons in program listings are all boxes with Unicode values in them.
This was working fine yesterday, and I am not aware of any updates to my system or to cargo. Going online to https://doc.rust-lang.org/book/ is just fine.
What’s going on?