Not that it's anything like Emacs, but would SIM Application Toolkit be considered kind of similar? It provided almost a lowest-common-denominator user interface for apps, which could actually run in the smartphone era, although with practically no advantages over a native app.
You'd be surprised to hear STK is still in use even today by big mobile operators. Some even go as far as to launch campaigns to install STK applets on millions of devices and customers have no idea this is happening in the background.
Yes, all the "eSIM" over-the-air management uses the STK for example. But to be fair, the user interface part is no longer used. The part of the STK still in use is what is required to support remote management functions between the network operator and some applet on the SIM card. The user is out of the loop, and it's perfectly fine for a modem not to support the user interaction part of the STK.
I actually work within the eSIM ecosystem and other sim related activities. And, yes, some mobile operators do indeed use the STK UI today, it's not limited to background tasks.
