Safari 26 helps many websites feel more like real apps on your iPhone and iPad....

https://touch-wiki.win/index.php/How_Do_I_Know_If_a_Home_Screen_Icon_Is_a_Web_App_or_Just_a_Shortcut%3F

Safari 26 helps many websites feel more like real apps on your iPhone and iPad. When you add a site to your Home Screen, it can open in a special full-screen mode without the usual browser bars getting in the way