If you roam around a TFS/VSTS Team Project Administration page you will surely come across the Services tab:
What am I supposed to do with these? Why is there “Endpoints” and “XAML Build Services”?
Let’s start with the first question – in VSTS or TFS you can connect external services to interact with various features, like Build or Release Management.
Azure is a great example in that regard, because you can link a subscription to a Team Project for deployment purposes, once you do so all the combobox related to Azure Deployment (ARM, Web App, Cloud Services) will be automatically populated.
But there is not only Azure:
The Generic Service Endpoint enables third party services like Perfecto to integrate with the platform – you need to provide a URL and some authentication.
Subversion? Yes, also SVN is supported on VSTS and TFS 2015.1. It is something new – the Java ALM team delivered this integration to enable Subversion as a repository for build definition. Kudos to them!
Jenkins is for the build engine as well, so you can use it in the OOB build tasks.
Now onto the second question – the separation between XAML Build Services and other Endpoints is because the former handles services in a different way.
But as it is more and more becoming something old and deprecated, only Azure is available for these. Moreover, the XAML Build Service Azure integration doesn’t support Service Principals out of the box so you need to customise it should you use them.