Can grad-cam be used for yolov5?

[achel-x]

Thanks for your work.
I read the paper and I have some questions about the usages of grad-cam.
The paper mentioned that grad-cam can be used in another cnn-based method. I wonder if yolo can use it.
Another question is that like these pictures

There are many objects in an image. Does it only show one class of these things?