On CPQ, how to get the list of attributes that are part of a document designer template?

Summary:

We are looking to get the list of attributes that are part of the document designer template.

Content (required):

Using the "Get Attribute Metadata" REST API, we have managed to list out all commerce attributes present in the application. Now we are looking to list the attributes that are present in any of the document designer templates.

We have tried downloading the template XSL, but since it is a large template with many sections and attributes (1000+ lines in the XSL), the complete XSL file is not loading on the browser.

Version (include the version you are using, if applicable):