You are using staging server - a separate instance of the ESP Component Registry that allows you to try distribution tools and processes without affecting the real registry.
To create a project from this example, run:
idf.py create-project-from-example "test_component_manager/test_87a7bd53-e4b3-4beb-9a24-c2e5375d7b71_yankable=1.0.0:cmp_ex"