Do not install. This app is requesting a stores "cart.js" every 100ms. Very sketchy and can't recommend to install that!
Thank you for your review. Reviews like yours help us improve the app for the benefit of all Shopify users.
The app is using Shopify's standard Ajax Cart API and checks the number of items that are in the cart in order to allow the Tab Animations to appear only if the cart is not empty.
I've sent you a detailed programmatic explanation via private email but got no response. I'll be happy to answer any other question you have.