Some random thoughts about extra syntax:
This is misleading. What it actually specifies is that whenever syntax specifies text "(", use some default values. So it should be just "token" syntax. It can also provide meaningful defaults for spacing hints, so that I don't have to include markers at every position:
Something along these lines:
These markers are hardcoded, as far as I understand and doesn't provide any hint of how to use them, how to make own, how to override behaviors, etc. Need to do something with this.