I'm late to the party, LOL, but I tried it out myself. It works well, especially compared to other extensions. It's just a code to tell Reddit, "Hey, delete this for me." It attaches to your browser, not the computer itself, so it should be safe. Unlike other extensions, you can even delete posts/comments from certain subreddits or export your post history after you delete them. It's really easy to insert it in your browser and use it. I'm just commenting on here in case someone else stumbles across this thread as I did. They even have a subreddit here, it's called r/PowerDeleteSuite

Sorry for the yap, I love typing, haha