This is a Ferrari engine - they are starting out buying them from Ferrari while designing their own. Currently expecting to switch in 2029. It’s quite normal for even top F1 teams to buy engines from others, BTW (last year’s winners, McLaren, have been purchasing Mercedes engines for years).

The car is their own design - I think that’s required for all teams.

https://www.formula1.com/en/latest/article/cadillac-provide-update-on-when-in-house-f1-engine-might-make-debut

Fascinating - thanks for posting!