The App documentation feature doesn't seem to be available with On Premise deployment. Current deployed version is 2.74.18
Hi there Phillippe!
Thank you for writing in
This feature has actually not been released to any on-prem versioning yet. Good news though, I went ahead and enabled this feature for your org. Please restart your container and you then should have access to it!
That explains it, thanks for enabling it for our Entreprise account, we'll test it out.