Chabad.org — English translation + Rashi
Torah Temimah points to Toras Kohanim (Sifra) on 3:3.
Sefaria — Sifra / Toras Kohanim
English: “From the sacrifice of the shelamim” — to include even though he slaughtered it not for its own sake.
Ribbuy of mizbach ha-shelamim — includes the emurim even after shelo-lishmah slaughter.
Emurim of shelamim are still offered even if the shechitah was not for the sake of shelamim. The Sifra treats the opening phrase as a deliberate inclusion that prevents the later offering of the fat from being disqualified by a prior intent defect. The sacrificial fat therefore remains eligible for the altar despite the flawed slaughter.