This attribute acts in a similar way to content attribute, instead of replacing the content of a node, will replace the node itself.

Suppose to have a variable foo with a value My name is John and the following template:

<div id="pagination" t:replace="foo">
    This <b>content</b> will be removed

The output will be:

My name is John

This can be useful to put come “test” content in your templates that will have a nice aspect on WYSIWYG editors, but at runtime will be replaced by real data coming from variables.