Chromium's sandbox's main innovation was shoehorning Windows' permission model into a sandbox without having to modify the operating system. It's a masterpiece,

Chromium's sandbox's main innovation was shoehorning Windows' permission model into a sandbox without having to modify the operating system. It's a masterpiece, don't get me wrong, but it doesn't transfer well to establishing good sandboxes on other platforms. Chromium's macOS sandbox just uses the one built into the OS and the Linux one doesn't leverage the effort put into the Windows variant either (though there is no need to anyway). That said, the fact that Apple's sandbox relies on inserting a full Lisp implementation into the kernel has always rubbed me the wrong way. I'm not sure if anybody is very good at this yet.