Yes you answered my question, I wanted to know if it was possible to add as a template one of the application listed in the github after clicking the "Make a Web Application" button.
I was looking for a way to create a web viewer application in JavaScript and upload it in ArcGIS Online. The standard templates do not have all the features I need.
How do you customize an ArcGIs Online application for example showing the list of layers with check boxes and allowing the user to check/un-check them.
Also adding different search criteria, by address, intersection folio, etc