Winterizing AGP - skimmer plate?

We've finally had the time to drain down the pool and disconnect the equipment. Just in time, since yesterday morning there was a thin film of ice on the water.

In the past we've always attached the solid metal plate in front of the skimmer opening. Not sure what that does and why we did it and am hoping someone can explain its use and purpose.

The water drains to just below the skimmer since the lowest opening in our pool is where the light fixture goes and we take that out. We disconnect the plumbing from the skimmer to the equipment and store the pump in the basement. We put a couple layers of wire mesh screen over the open ends of the pipes and there's a skimmer basket inside the skimmer pot. So essentially the system is sealed against critters but water could flow and ice has room to expand.

Do we still, or should we, need to install that cover?

Are you asking if you need the metal plate in front of the skimmer or if you need to cover the pool with a winter cover? I do neither.

I was asking about the metal plate in front of the skimmer. We don't cover the pool. Just wondering what the purpose of that metal plate is.