This doesn't have a name and its only sort of a recipe, more of a suggested guideline perhaps. The proportions really depend on the flavor and intensity of your ingredients. Over the winter I've been brewing kombucha until its super sour then cutting it with sweeter fruit juice or ginger beer or anything else I can find. On this occasion, I took some kombucha before it was fully fermented, so it was sour but also still sweet. I made a shrub over the winter with some random cheap out of season berries. I don't know what recipe I used or if I messed it up, but it is also sweet and sour. Shrubs should be but this one is really sweet with a hint of tartness. So this recipe works really well for the ingredients I had but may not be reproducible.
Kombucha in mocktails works very well because it is so intensely flavored. It has the oomph that a soda or fruit juice is lacking. I've been using club soda to stretch out the flavors if I use other intense ingredients like lemon or lime. I'll also use sparkling wine if its for someone that drinks alcohol but doesnt want a big drink.