Filtered attribute values are indicated with triple curly braces around a Filter Expression. The value will be the first item in the resulting list, or the empty string if the list is empty.

Introduced in v5.2.2 To improve readability, newlines can be included anywhere that whitespace is allowed within filtered attributes.

This example shows how to add a prefix to a value:

<$text text={{{ [<currentTiddler>addprefix[$:/myprefix/]] }}} />