Input:

<!ENTITY % brandDTD
    SYSTEM "chrome://branding/locale/brand.dtd">

<!ENTITY % 	brandDTD	
	    SYSTEM "chrome://branding/locale/brand.dtd" >


<!ENTITY	 % 	 brandDTD
    SYSTEM
		"chrome://branding/locale/brand.dtd"
	>

<!ENTITY	 % 	 brandDTD



    SYSTEM



		"chrome://branding/locale/brand.dtd"


   >


Result for all:

<!ENTITY % brandDTD SYSTEM "chrome://branding/locale/brand.dtd">