You can use it. Theme.properties
must be created. It is not their by default.
Here is what I have...create it at root level..
But why do you say that you need this file to create Viewport? This file doesnt do all that. It only helps control the listed attributes. I am not sure how things have changed in help center though. I have not yet upgraded to helpcenter version...theme.plugin.key=com.mycompany-theme-plugin
theme.plugin.name=mycompany
theme.plugin.version=1.1
theme.plugin.module.key=mycompany-theme
theme.description=This is MyCompany Scroll Viewport theme for customer-facing online documentation.
theme.enableViewportControl=false