The model number for the Porcelain variant (which is white) is GA04750-JP. We assume that the “JP” after the hyphen is Google’s country code for Japan. The Hazel variant is listed as being out of stock although we don’t know whether this is posted as such simply because the device has yet to be officially announced.
We expect the Pixel Tablet to feature a 10.9-inch display with a 1600 x 2560 resolution and the device will be powered by the Google Tensor 2 SoC. That is the same chipset that powers the Pixel 7, and Pixel 7 Pro, and is also expected to be under the hood of the soon-to-be-announced Pixel 7a mid-ranger. The latest rumored specs have the slate carrying 8GB of RAM and the storage options are expected to be 128GB/256GB. Android 13 will be pre-installed.

Amazon Japan accidentally publishes its Pixel Tablet page
The accidentally posted Amazon Japan page also reveals that the Pixel Tablet will come with a charging speaker dock that effectively turns the tablet into a smart display.