It’s legit, but I understand if you’re skeptical, I wouldn’t click on some random link either lol but I can confirm it works
Here’s a screenshot of my zap symbol running Damus. That definitely wasn’t there prior to running the script. https://image.nostr.build/4748ac7cb993f4b3e375458266bcac36947887c02815e7ee015adc941edfd190.jpg
Yep! I've recommended this to as many Damus users as I find that want Zaps back.