they did mention it in the long description. It's off for now but they are planning on turning it on.

I'd guess it's safer than JIT because the translation to assembly is simple, or can be simple. It's not trying to do the complicated process of analyzing a dynamically typed language and applying different ways of optimizing.

I bet they'll end up using a pure bytecode interpreter for Web Assembly as well, that just runs the operations one by one instead of converting them to machine code. It'd be the same "slower but safer" trade-off that the mode uses for regular Javascript.

I’m sure there’s a great reason but the policy description reads like ‘turn this on for more security and no important downsides’

> Disables the JIT and enables new security mitigations to provide a more secure browsing experience - Windows