I am not sure who the originator of the idea was (not me!). I think the syntax has existed prior to Obsidian in other tools.
The suggestion originally came on my radar via @ryanjamurphy in issue #8 of Minimal theme referencing a snippet by @death.au
Minimal’s implementation was late to the party and took inspiration from Sanctum, Primary and ITS Theme. However each theme has slightly different syntax so I tried to follow the conventions that are common across themes, and added a couple of my own.
The available options can be referenced in the Minimal Documentation
