Green Screen Plus Symbols

I noticed that the green screen backgrounds have ‘+’ symbols in the green area. I’m not sure why this is but it causes problems when I chroma key. Any suggestions on how to work with that? The green chroma key works well in DaVinci Resolve but the final image has 5 plus symbols on it. Thanks.

Disregard. I understand now that those are tracking markers. And to remove in DaVinci you just paint over them.