Index: wp-admin/themes.php
===================================================================
--- wp-admin/themes.php	(revision 26152)
+++ wp-admin/themes.php	(working copy)
@@ -264,7 +264,11 @@
 				<span class="current-label"><?php _e( 'Current Theme' ); ?></span>
 			<# } #>
 			<h3 class="theme-name">{{ data.name }}<span class="theme-version"><?php _e('Version: '); ?> {{ data.version }}</span></h3>
-			<h4 class="theme-author"><?php printf( __( 'By %s' ), '<a href="{{ data.authorURI }}">{{ data.author }}</a>' ); ?></h4>
+			<# if ( data.authorURI ) { #>
+				<h4 class="theme-author"><?php printf( __( 'By %s' ), '<a href="{{ data.authorURI }}">{{ data.author }}</a>' ); ?></h4>
+			<# } else { #>
+				<h4 class="theme-author"><?php printf( __( 'By %s' ), '{{ data.author }}' ); ?></h4>
+			<# } #>
 
 			<# if ( data.hasUpdate ) { #>
 			<div class="theme-update-message">