The F.T.C. asks for an extension to refile its Facebook antitrust suit. The Federal Trade Commission on Friday asked a federal judge to give it more time to refile an antitrust suit against Facebook that is the agency’s biggest test in reining in the power of big tech. In a filing with the U.S. District Court for the District of Columbia, the agency asked for a three-week extension, or until Aug. 19, to amend a lawsuit that the court dismissed last month. The F.T.C. said in its request that it had reached an agreement with Facebook over the proposed extension.