All the way up until the first deliviries of the Tesla Model Y, Tesla has been keeping some details closed to outsiders.
On March 1, 2020 (14 days before the first scheduled deliveries), these spy photos were posted on Twitter. They show the interior of the Model Y, which, until this point, was basically unseen.
It looks very similar to the Model 3, perhaps with more headroom, and a slightly different center console. In the spy photos, there is no third row seat, just an empty, large cargo space underneath the hatchback.
The glass roof looks like the glass roof on the Model 3 as well.
Some comments under the Twitter thread speculate the rear-seat charging ports are USB-C, and that there is no retractable cargo-cover hooks in the rear.