When a user clicks the word LINK, the instance prompts the user to log in if not already logged in, and then redirects the user to the record specified in the URI.

The ${URI} parameter has an extension called the ${URI+} format to specify additional arguments in the email link, such as sysparm terms, in addition to the automatically created URI. For example (whitespace added for improved readability):

${URI+&sysparm_scriptlet=current.assigned_to=gs.getUserID()
&sysparm_scriptlet_condition=current.assigned_to.nil()
&sysparm_view=incident_active}

This example executes the JavaScript:

current.asigned_to=gs.getUserID()

when the condition of

current.assigned_to.nil()