T-Mobile Netherlands is a national division of a carrier that also sells accessories for flagship iPhones from 2018, 2019...and 2020. It names these devices according to their individual variants, and also has live pages for a few cases that may indeed fit them accurately - despite the fact they are still probably months away from launch.
https://www.notebookcheck.net/A-carrier-s-online-store-now-stocks-cases-for-the-iPhone-12-series.478108.0.html