The format directive is supplied by the format plugin.

The directive allows formatting a chunk of text using any available page format. It takes two parameters. First is the type of format to use, ie the extension that would be used for a standalone file of this type. Second is the text to format.

For example, this will embed an otl outline inside a page using mdwn or some other format:

[[!format  otl """
foo
    1
    2
bar
    3
    4
"""]]