thunderbird.VisualElementsManifest.xml

Enable keyboard shortcuts

<Application xmlns:xsi='http://www.w3.org/2001/XMLSchema-instance'>

  <VisualElements

      ShowNameOnSquare150x150Logo='on'

      Square150x150Logo='VisualElements\VisualElements_150.png'

      Square70x70Logo='VisualElements\VisualElements_70.png'

      ForegroundText='dark'

      BackgroundColor='#c4d3d3'/>

</Application>