There is no one mark down. The closest thing to a standard that exists is common mark mark down, which is like an attempt at standardization across a few different communities. People often talk about mark down in terms of flavors: what functionality do you want to turn on? And there 're a couple of nites, like renders and parcers, that will let you enable extensions in mark down to turn on and off different kinds of syntax. So it's kind of intentionally trying to create like a privileged extension point, either for block level writing or for inland writing.