Docs probably not been updated to account for the changes, since no one has thought to raise a docs update request based on changes to GA. And GA can change on a dime half the time.
Edit: Filed as 277 Google Analytics in extensions: example not up to date with GA changes · Issue #277 · twitchdev/issues · GitHub
And I was quick since I still had the tab open from when it was discussed in the Dev Discord recently.