CreateAccount.template - represents the HTML for the Create Account dialog (registration form) 
JoinMeeting.template - represents the HTML for the header of the grid from the Join Meeting dialog 
ManageAccount.template - represents the HTML for the Manage Account dialog (authentication form)
StartMeeting.template - represents the HTML for the Start Meeting dialog 
StartMeetingEmail.template - represents the HTML form of the AnyMeeting invitation email 

The corresponding JS files from the Templates folder are automatically generated by Zimbra when the Zimlet is deployed (more precisely, based on template files, Zimbra creates scripts and uses them for actually creating the layout defined by the user in the template files). 

Note: As you will see, the templates contain HTML controls with specific ids which are used in code, more precisely in the functionalities implementation. Therefore, in case you change the id of a control, you will also need to update the functionality accordingly. 