A controller that operates a search engine must publish, in an easily accessible place that needs no login, an up-to-date plain-language description of the main parameters that most significantly determine ranking and their relative importance, including any prioritisation or deprioritisation of political partisanship or ideology. Algorithms, and information that would enable manipulation of results, need not be disclosed.
The graph holds this control, the 0 it maps to, and the evidence behind each claim, over MCP and REST.