@HarpSong @blobcat @t2pub Ahh. It doesn't work with PWA (Progressive Web Apps).
In the original pebble.is, I installed it as a PWA and works great that way. It's actually where websites are headed in the future, less consumption of resources (skills, time, money) since it's basically a mobile version of the website only, not a native app.
I'm not sure how it works with Apple devices, but for the #Firefish fediverse software, its PWA for Apple devices works fine. So, I understand Apple's Safari browser supports PWA.
If you haven't tried PWA yet, you can check https://phanpy.social and login using your existing Mastodon account. You can use Firefox or Chrome. After logging-in, click the menu of the browser, and you should see something like “Install”.
It will create an icon on your device. Close the browser, then tap on the icon. It will load the mobile version of the website as if it is a native app.