Description about Customization.xml

I want to add a button to a ribbon and I googled and found how to add a button. Where can I find description about the each element in customization.xml file?

e.g.,

ImportExportXml->WebResources->CanBeDeleted

 <WebResources>

   <WebResource>

     <WebResourceId></WebResourceId>

     <Name>Application_ribbon.js</Name>

     <DisplayName>Application_ribbon</DisplayName>

     <Description>Default Ribbon Library</Description>

     <WebResourceType>3</WebResourceType>

     <IsCustomizable>1</IsCustomizable>

     <CanBeDeleted>1</CanBeDeleted>

     <IsHidden>0</IsHidden>

     <FileName>/WebResources/Application_ribbonjs</FileName>

   </WebResource>

 </WebResources>