John Gill Commentary Leviticus 9:19

"and the fat of the ox and of the ram, the fat tail, and that which covereth [the inwards], and the kidneys, and the caul of the liver:" — Leviticus 9:19 (ASV)

And the fat of the bullock, and of the ram Which in all offerings was the Lord's, and was burnt, see (Leviticus 3:16) the rump ; or tail of the ram; which in those countries was very large, and had a great deal of fat upon it; (See Gill on Exodus 29:22) (See Gill on Leviticus 3:9) and that which covereth [the inwards] ; called the "omentum": and the kidneys, and the caul [above] the liver ; and the fat that was upon each of these: Ben Gersom observes, that the kidneys and liver are mentioned last, to show that they were laid uppermost in waving (after directed to), that the owners might be stirred up, or moved by these things.