That appears to be a repair kit for a damaged thread in the oil pan. The big plug probably has an oversized, self-tapping thread and the middle plug is then used to drain the oil. The bracket that's held on by the screw is a safety device to prevent the plug from getting loose and backing out. The inventor of that device was probably a gentleman named Goldberg!
Jerry

"It is better to be silent and be thought a fool than to speak and eliminate all doubt!" - Abraham Lincoln
Cringe and wail in fear, Eloi- - - - -we Morlocks are on the hunt!
There is nothing noble in being superior to your fellow man; true nobility is being superior to your former self. - Ernest Hemingway
Love your enemies and drive 'em nuts!