Sometimes, it's useful to explain what you are doing when writing complicated templating code. In that case you can use comments to document what you are doing. You can also use comments to add general info to the template (like in the example below).
{! <COMMENT TEXT>}
The <COMMENT TEXT> can contain
any characters you like, except for "}".
Example 1.14. Add in line comments
{! This template was created by John Doe and his lovely wife Jane }