code: function suffixThemeIdForInstall( state, siteId, themeId ) {
  	// AT sites do not use the -wpcom suffix
  	if ( isSiteAutomatedTransfer( state, siteId ) ) {
  		return themeId;
  	}
  	if ( ! isDownloadableFromWpcom( state, themeId ) ) {
  		return themeId;
  	}
  	return themeId + '-wpcom';
  }
docs: Install of any theme hosted as a zip on wpcom must
  be suffixed with -wpcom. Themes on AT sites are not
  installed via downloaded zip.
  
  @param {Object} state Global state tree
  @param {number} siteId Site ID
  @param {string} themeId Theme ID
  @return {string} the theme id to use when installing the theme