Online Access to Materials Harmful to Minors; Requires developer & covered manufacturer to, beginning on specified date, make specific determinations about covered applications & user, provide certain notices, & provide certain features to parents & developers; provides requirements for devices sold before specified date; requires application store to establish nondiscriminatory practices; provides for enforcement actions by Attorney General; provides affirmative defense; provides limitation on liability for covered manufacturer; revises age verification method used by certain commercial entities to verify age of person accessing certain material; provides exception; requires covered manufacturer to ensure certain statutory requirements are met; authorizes DLA to bring action against covered manufacturers; authorizes imposition of civil penalties against covered manufacturers; removes certain liability & damage provisions for certain commercial entities; removes provisions relating to public records exemptions & OGSR; requires covered manufactures to take certain steps upon activation of device; requires certain websites, applications, or online services to take certain actions based on amount of material harmful to minors found on such website, application, or online service; requires covered manufacturers to comply with statutory requirements in nondiscriminatory manner; prohibits covered manufacturers from taking certain actions; authorizes DLA to adopt rules & regulations; provides preemption.