Torgeek
Tor Browser in its default mode is starting with a content window rounded to a multiple of 200px x 100px to prevent fingerprinting the screen dimensions. The strategy here is to put all users in a couple of buckets to make it harder to single them out.
Why is Tor not full screen?
That concern is secondary and not a strong reason for keeping the window small, basically websites can see your screen resolution and if you're having a different resolution than other users they can narrow down there search results. Thats why it is not recommended to run tor in full screen.
What is Tor window?
Tor, short for The Onion Router, is a free, open-source web browser that helps people use the internet anonymously. However, Tor has some privacy limitations and may not be necessary for your everyday online activity.
