In forge api documentation we can find: https://forge.autodesk.com/en/docs/bim360/v1/reference/http/projects-project_id-industry_roles-GET/
It gives us all available roles in projcet. On https://docs.b360.autodesk.com it seems to be reduced to roles which available users have (and fore example shows only 3 roles insted of all 36) How can we connect users with roles?
Unfortunately, The API to GET the users information of a project is not exposed yet, I know it's a frequently asked request, and our engineering team is still working on this. Without this API, I can not think a way to identify all the industry roles that are available within this project. Sorry for the limitation.