Evaporator extra drain?

Never seen this set up before. 2018 Lennox evaporator unit. It has the main condensate drain, the auxillary drain with a float switch, and then this clear tube exiting the housing going to the floor drain. There is a decal on the evaporator saying in 2018 the evaporator was treated with an 'anti-microbial. There is also what looked like a 3 conductor NM going from the burner section and entering the evaporator where the drain line exits.
I have called the company that did the installation but only talked with the scheduler. Hoping to have a technician or supervisor call me some time today.
Have any of you seen something like this?

OK, the HVAC installers called me back and said they had installed a sump pump in the supply plenum. This is a down draft unit, with under slab PVC ducts. I have asked for a reason they installed this, but he has to go back and do more research. Also I noticed when looking at the 3rd picture, the grounding conductor for the (now known) sump pump is not connected.
Any thoughts?

The are obviously anticipating some condensation at the lowest point of the plenum or needed a back-up pump in case it did condensate.

I am curious what the install manual says about a downdraft unit and condensation control.