How to delete a project or revoke FireCMS access to the Firebase project

[salatielsql]

I created a test project on Firebase and then created linked the project to the FireCMS app. After that I tried:

• Go to my Google Account dashboard and revoked the firecms access from there
• Find a delete project button on the FireCMS web app

How can I delete the project or better revoke FireCMS access to my Firebase project?