I am new to Composite C1 - and am using Page Template Features.
I have noticed in the sample file that some are market .html - and some marked .xml (even though the latter appear to just be html pages).
is there a reason for this? Do I need to be aware of it?
In the C1 Console, .html-based features will open in Visual Editor, .xml-based - in Code Editor.
For more information, please see http://docs.composite.net/Layout/Page-Template-Features/Creating#Visual-vs-Markup
For a lengthy technical discussion on this feature, please see http://compositec1.codeplex.com/discussions/404072