WRKCO INC. as Issuer and WESTROCK COMPANY, WESTROCK MWV, LLC and WESTROCK RKT, LLC as Guarantors THIRD SUPPLEMENTAL INDENTURE Dated as of June 3, 2020 to INDENTURE Dated as of December 3, 2018 THE BANK OF NEW YORK MELLON TRUST COMPANY, N.A. as Trustee...