Plastic sheeting under shower?

2015 Itasca Sunstar. We have some kind of small water leak from the shower. In trying to diagnose it I see that there is some clear plastic sheeting on the linoleum under the front edge of the shower. Again, on the floor under the shower. It runs horizontally from the right-hand edge of the shower, past the left edge, and on under the refrigerator. It's relatively thin plastic sheeting, maybe 5 inches deep. It seems its only purpose is to trap the water leaking from the shower and hold it against the linoleum floor and prevent it from evaporating! That is, it's wet underneath this plastic sheeting. I'm tempted to rip it out but thought I'd better run it by the forum before I do. Anyone know what purpose this sheeting might have?

dave