Safari 26 on iPhone and iPad brings a fresh feel to many websites by making...

https://bizzmarkblog.com/why-does-my-ipad-web-app-feel-different-from-the-same-site-in-safari-tabs/

Safari 26 on iPhone and iPad brings a fresh feel to many websites by making them act just like apps. When you add a site to your Home Screen, it now launches without the usual browser bars, giving you a clean, full-screen experience