That front wing and engine cover part look quite interesting. The engine cover looks a bit borrowed from Mercedes. They will be still the team to beat this year.
It's legally a RBPT(redbull powertrains) engine. But it's entirely based on what Honda was making for them, like they literally took over the project as it stood and are still supported by Honda for a couple more years I think. A quick wiki search also suggests that Honda still assembles the engines and still own the IP on them due to a development freeze.