It predates dolphin's use of it, though don't ask me by how long. Here's a reference to the term from 2008: https://realtimecollisiondetection.net/blog/?p=73
Ubershader actually has three different opposite meanings, unfortunately.
The classic usage is a single source shader which is specialized using #define's and compiled down to hundreds of shaders. This is what Christer uses in that blog post above (and Aras does as well in his ubershader blog post)
Dolphin used it to mean a single source shader that used runtime branches to cover all the bases as a fallback while a specialized shader was compiled behind the scenes.
The even more modern usage now is a single source shader that only uses runtime branches to cover all the features, without any specialization behind the scenes, and that's what Dario means here.
Ah, then my correction probably does not stand, and I'll need to look deeper into it. Thanks for the explanation! This jargon really gets out of hand at times. :P But I don't mind being wrong if I learn from it.
Thank you. This is my favorite kind of comment. There are lots of "technical" terms which manage to acquire similar but distinct uses (today I was contending with "agent" and "prompt"). Keeping them straight in your own head, and recognizing when others don't is as valuable as it is unappreciated.