Why the description of Page Layout is not showing

When custom page layouts as part of a feature, the internal name for "Description" is "MasterPageDescription".

<?xml version="1.0" encoding="utf-8"?>
<Elements xmlns="http://schemas.microsoft.com/sharepoint/">
  <Module Name="MasterPageGallery" Path="MasterPageGallery" Url="_catalogs/masterpage">
    <File Url="ApplicationLayout.aspx" Type="GhostableInLibrary">
      <Property Name="Title" Value="Application Layout" />
      <Property Name="MasterPageDescription" Value="Use this layout to include other web applications inside SharePoint" />
      <Property Name="ContentType" Value="$Resources:cmscore,contenttype_pagelayout_name;" />
      <Property Name="PublishingPreviewImage" Value="~SiteCollection/_catalogs/masterpage/$Resources:core,Culture;/Preview Images/ApplicationLayout.png, ~SiteCollection/_catalogs/masterpage/$Resources:core,Culture;/Preview Images/CustomPageLayout.png" />
      <Property Name="PublishingAssociatedContentType" Value=";#$Resources:cmscore,contenttype_articlepage_name;;#0x010100C568DB52D9D0A14D9B2FDCC96666E9F2007948130EC3DB064584E219954237AF3900242457EFB8B24247815D688C526CD44D;#"/>
    </File>
</Module>
</Elements>