Safari 26 improves how websites work on iPhone and iPad by making them feel...

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

Safari 26 improves how websites work on iPhone and iPad by making them feel more like native apps. When you add a site to your Home Screen, it now launches in a clean web app mode without browser bars or tabs getting in the way