Impersonating OAuth using Application Links is supported.

The URL configured with projectdoc (for example as a space property using the url- prefix) needs to find a prefix URL configured as an application link. So the URLS of the system link and the Application Link have to match, not the prefix of your defined url-property and the name of the Application Link The first match is used to authenticate to access a protected resource on the remote service.

Currently not supported.

Basic authentication using HTTP headers is supported.

A Basic Authentication Link is also established using the Application Linksadmin page.

This time you do not create an impersonating OAuth Link but an Application Link with Basic Authentication.