Hi Nicholai! When you get a chance, please introduce yourself here. I'd also encourage you to add a real picture as your avatar because it helps build community.
Central has a fully-featured REST API that works great with curl. That API that is documented at https://odkcentral.docs.apiary.io. There is also link to this documentation at https://docs.getodk.org/central-api. Have you had a chance to look through the API docs?