Washer hookups and the washer drain.
Looks like someone put an adapter on one if the hose bibs for who knows what reason?
Maybe the bib leaked slightly and this was their way of stopping it.
It very well could have been an easy way to get antifreeze in/out of those supply lines too.
You'll find LOTS of things not covered in the very generic owners manual. Lots of rigs don't even come with a manual.
2016 Flagstaff 8529IKBS Diamond Package 5th Wheel-Goodyear Endurance Tires
2017 Ford F-Series SCREW 4x4 - Factory Puck B&W Companion
TST Tire Monitor w/Repeater - Sinemate 3500w Gen.
Days Camped: '18=51 ☼ '19=58 ☼ '20=110 ☼ '21=60