Incognito mode is also known as 'Private browsing'. Earlier it was limited to browsers only where after enabling this mode a temporary session of browsing used to get activated where no history was saved.
Now recently Youtube got an incognito mode to browse youtube anonymously without leaving anything in the watch history.
Google Maps version v10.28.2 has the incognito mode in it.
After enabling the incognito mode it will look like this
The update has rolled out just a few hours ago so it might take some time to reach each and every one of you out there so kindly wait. Also, the update has started from Android first and it will soon reach iOS devices too.