Safari 26 makes using websites on iPhone and iPad feel more like using apps....

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

Safari 26 makes using websites on iPhone and iPad feel more like using apps. When you add a site to your Home Screen, it now launches without the usual browser bars cluttering the view