X0306 4 2022-07-01 0 0001567892 Mallinckrodt plc MNKPF 0001927125 Celentano Daniel Arthur 675 MCDONNELL BLVD. HAZELWOOD MO 63042 1 0 0 0 Restricted Stock Units 2022-07-01 4 A 0 48809 0.00 A Ordinary Shares 48809 48809 D The grant of restricted stock units vests in equal installments on each of the first and second anniversaries of the date of Mallinckrodt plc's emergence from bankruptcy (June 16, 2022). Each restricted stock unit represents one Ordinary Share, and may be redeemed in either cash or stock. This Form 4 constitutes a notice to the Issuer for purposes of Part V of the Companies Act 2014. /s/ Mark J. Casey, Attorney-in-Fact 2022-07-06