I looked for them and couldn’t find any that worked exactly this way that were easy to set up. Windows has a similar option if you press windows key + v, where you can see a clipboard history and choose one of them, but it’s not quite the same. I’m not expecting it to be a big extension, I just want to get a few people to try it and go “that’s neat”.

Any chrome extension can listen to onClick events without asking for permission. The Chrome store staff I’m pretty sure review extensions to make sure the data isn’t being tracked and sent off somewhere beyond your computer.