There's a red "1" notification on the Settings button at the bottom right, but I have no idea what it is.
Clicking on the button just opens Settings, no markings saying what the notification is related to.
Poking around a couple of settings didn't reveal anything.
On Android, v2.24.0
FIXED - It was a notification that an upgrade was available.
Yeah... some nerd details: Capacitor v7 enabled service workers in Android (kinda). Which is great, but I wasn't expecting that. And so the native android app is checking for PWA updates, finds an update, but the PWA menu to update is disabled in the native app.
The fix basically just disables the service worker code completely for the native app. Probably should have been done before, but again, in capacitor v6 service workers weren't a thing, so it was effectively disabled anyways then.