They are paying them not to develop a competitor search engine* and not to default include adblock, not to mess with cookies ect. That doesn't need to be in the

They are paying them not to develop a competitor search engine* and not to default include adblock, not to mess with cookies ect. That doesn't need to be in the agreement but it is obviously implied. "Would google still pay us $10 billion if we did X?" is enough to do it. * or more accurately keep it in the development phase for almost a decade now.