Strange...clicking Ctrl+. in my Firefox (which I just updated to 150.0.1) did not bring up the Emoji Picker, but instead brought up Firefox Multi-Account Containers.

Sounds like you might be on macOS? (or Windows, given you write Ctrl rather than Cmd?) https://news.ycombinator.com/item?id=47961337

In hindsight, I probably should have made it clear that this change is for Firefox 150 on Linux specifically.