If you use http://realfavicongenerator.net/ it generates all the relevant icons, incorporates this very same 'one weird trick' (a manifest.json), plus some additional extras like a SVG macOS touch bar icon.

No affiliation, just a user of their free service who was impressed enough to donate to them as it's extremely useful and well done.

The title is clickbaity and against the guidelines, can we change it to something like "How to turn your ..." or "A trick for turning your ..."?

I think the title is being satirical of the current state of web development, which is often needlessly complex.

"One weird trick" is something we associate with class of false advertisements. The irony is that we don't expect turning a website into an app to be easy, but it turns out it is.

Perhaps you were being humorous as well?

And it's not even faithful to the actual (though largely uninformative) original title.

https://archive.fo/rK3OU

I was going for humour. I don't know how to change it.

Android only, or have I missed some news? Really wish iOS would support this already. HTML5 offline does similar, but cache/update scenarios can be tricky.

Well one can wrap a url into a cordova view, then distribute that. not as immediately easy, but can be made a one click self service. I sense there's enough space/demand for a startup there.

Maybe Apple will come to their senses when >50% of Android apps are PWAs.

Till then I'll use Exponent I guess

This feature is already in iOS. Goto mobile Safari. Under sharing there's "add to home screen". Icons can be controlled through meta tags in the markup.