This displays the differences between the current state of a template and the original state of the template before it was customised.
It can be displayed by selecting a customised template in the Templates tree and selecting the Differences button on the template toolbar.
Here is an example of what it looks like:
This textarea displays the template in its current state. The number of differences between this and the original template is displayed in brackets.
This textarea displays the template in its original state, before any customisations were made.
This closes the dialog.