Mozilla is pressing on with its UI overhaul of Firefox. Now, from version 32 onward the Options window will be moved to an inline tab by default, but don't worry, it looks like you can still revert.
Windows 11 22H2 build 22621.160 (RTM) gets File Explorer Tab navigation
tabbed file explorer
Windows 11 in the Dev Channel fixes Windows Security app issues, and more
windows 11 insider preview