It's a Firefox thing. The context menu in pwa mode is different from the normal one. This is most likely a bug.
A workaround I sometimes use, is to go to the notification drawer, click the silent pwa notification to copy the URL of the current page, share the copied URL with firefox and finally use the normal context menu.
What you are referring to are androids custom tabs. It's an android feature where an app can request an "in-app" browser window from the systems default browser. The system also allows the app to specify some customizations like the color of the action bar and I think its possible to add some buttons as well.
Firefox supports this feature and many apps give you an option to turn it off, but it's up to the app opening the links.
Im not at all familiar with the processes of WebKit, but the commit that was the result of the PR which is referenced in the linked bug, is not part of any release tag yet. So it's unlikely that this change is available in any stable software that is built with WebKit (I.e. safari)
This is my ringtone: https://m.youtube.com/watch?v=Ljqe4Nj7nBA&pp=ygUKbG9zdCB3b29kcw%3D%3D
And this is my notification sound: https://github.com/mozilla-b2g/gaia/blob/master/shared/resources/media/notifications/notifier_dropplet.opus
You need to export them from your script.
Let's turn github into Instagram. Every snippet of code has to be attached to a picture or video...
This would most certainty be part of the used subscriber. I'm not sure if any of the existing subscribers support it, but in the worst case you can write your own subscriber that wraps an existing one.
Lazy-loading is exactly the opposite of pre-loading 😅
It should be possible to implement this for PWAs though. I.e. let the service worker respond with a custom manifest . it might just take some time until the browser picks up the change and updates the icon.
It depends on how you want to store your data. Every OS has a standard for where applications should store their data. You should store your data at the appropriate path. If you have structured data against which you want to run queries you could use a sqlite DB (the sqlx crate supports sqlite) instead of just a bunch of config files.
Advertising any kind of payment / subscription that does not go through the store through which the app has been distributed, is prohibited by apple and google (not 100% sure about google, but fairly certain).
No there is no way to customize the menu. I found an old bug that mentions adding a share option to the context menu. It is probably worth it to either kick this old bug, mentioning what is still missing, or to create a new bug describing the current issue.