Democrats Henry Waxman and G.K. Butterfield of the U.S. House Energy and Commerce Committee sent letters on Thursday to developers of iOS apps. The lawmakers are seeking the information as part of an inquiry into privacy and security practices related to mobile phone applications. The inquiry comes amid growing concern about mobile privacy, which remains largely unregulated despite the explosion of smartphone usage. In mid-February, lawmakers sent a letter to Apple CEO Tim Cook, requesting clarification of the privacy protections the company demands of app developers.”]