At a private meeting in September, congressional aides asked Rebeckah Adcock, a top official at the Department of Agriculture, to reveal the identities of the people serving on the deregulation team she leads at the agency. Teams like Adcock’s, created under an executive order by President Trump, had been taking heat from Democratic lawmakers over their secrecy. What little was publicly known suggested that some of the groups’ members had deep ties to the industries being regulated.