Chapter09 What does it mean that variables are "similar" to one another?

Part 1 (2020)
1

Screen Shot 2022-03-17 at 3.51.59 PM
Screen Shot 2022-03-17 at 3.51.59 PM2342×1230 195 KB

I’m having a hard time understanding what this graph means. Does it mean that the partial importance graph looks the same?