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_4812d78a-578f-45c6-86c0-2cd745fcc62c_yankable=1.0.0:cmp_ex"