Application Links over API Management

Hi everyone,

we are trying to connect a external hosted Jira and an internal hosted Bitbucket via the standard Application link. Our IT-Security demands that all incoming/outgoing traffic to/from our internal network has to go through our API Management. This is basically just a middleware that exposes an endpoint to the public and internal so that the systems don’t talk directly to each other but through the API Management. So something like this:
External----------------------------Internal
Jira <—>API Management <–> Bitbucket
This API Management then makes sure that the API request has the correct structure and validates the request token.
Our problem right now is that we do not know what kind of structure the Application link communication is using. For our solution to work we have to replicate this structure into our API Management. The best thing for us would be a documentation in the form of Swagger or OpenAPI. I did find Swagger for the Bitbucket API and WADL for the Jira API. Unfortunately Atlassian support was no able to confirm that the Application link is using these open API endpoints or internal non documented ones.
Can anyone help me out here or had a similar problem?
Thanks in advance

Christian

PS: The used products are Jira Data Center and Bitbucket Data Center.