Excludes from gross income certain gains when a taxpayer sells a qualified real-property interest to a qualified organization if the sale is for purposes of the Department of Defense Readiness and Environmental Protection Integration (REPI) program. The rule defines eligible property interests and eligible buyers, limits the exclusion for pass-through entities when the interest was itself acquired by sale within the prior three years (with an exception for family-owned pass-throughs), updates the Code table, and applies to tax years beginning after enactment.