This type of plan falls under Section 504 of the Rehabilitation Act of 1973. This is the part of the federal civil rights law that prohibits discrimination against public school students with disabilities which includes students with learning and attention issues who meet certain criteria.
Much like an IEP, a 504 plan can help students with learning and attention issues learn and participate in the general education curriculum. A 504 plan outlines how a student's specific needs are met with accommodations, and other services. These measures “remove barriers” to learning.
Keep in mind that a student with a 504 plan usually spends the entire school day in a general education classroom and typically, students who need modifications would have an IEP, not a 504 plan.