--- a/layout/mathml/operatorDictionary.xsl
+++ b/layout/mathml/operatorDictionary.xsl
@@ -42,16 +42,19 @@
           <xsl:if test="@*[.='true']">
             <xsl:attribute name="properties">
               <!-- largeop, movablelimits, stretchy, separator, accent, fence,
                    symmetric -->
               <xsl:for-each select="@*[.='true']">
                 <xsl:value-of select="name()"/>
                 <xsl:text> </xsl:text>
               </xsl:for-each>
+              <xsl:if test="../unicodedata/@mirror = 'Y'">
+                <xsl:text>mirrorable </xsl:text>
+              </xsl:if>
             </xsl:attribute> 
           </xsl:if>
           <xsl:if test="@priority">
             <xsl:attribute name="priority">
               <xsl:value-of select="@priority"/>
             </xsl:attribute> 
           </xsl:if>
           <xsl:if test="@linebreakstyle">

--- a/layout/mathml/updateOperatorDictionary.pl
+++ b/layout/mathml/updateOperatorDictionary.pl
@@ -292,23 +292,23 @@ for ($i = 0; $i < $n; $i++) {
     $_ = $entry->getAttribute("properties");
     $value[4] = (m/^(.*)largeop(.*)$/);
     $value[5] = (m/^(.*)movablelimits(.*)$/);
     $value[6] = (m/^(.*)stretchy(.*)$/);
     $value[7] = (m/^(.*)separator(.*)$/);
     $value[8] = (m/^(.*)accent(.*)$/);
     $value[9] = (m/^(.*)fence(.*)$/);
     $value[10] = (m/^(.*)symmetric(.*)$/);
+    $value[15] = (m/^(.*)mirrorable(.*)$/);
     $value[11] = $entry->getAttribute("priority");
     $value[12] = $entry->getAttribute("linebreakstyle");
 
     # not stored in the WG dictionary
     $value[13] = ""; # direction
     $value[14] = ""; # integral
-    $value[15] = ""; # mirrorable
 
     # 3.3) save the key and value
     push(@wg_keys, $key);
     $wg_hash{$key} = [ @value ];
 }
 $doc->dispose;
 @wg_keys = reverse(@wg_keys);
 
@@ -425,16 +425,17 @@ sub generateCommon {
     if ($v[3] ne "1") { $entry = "$entry minsize:$v[3]"; }
     if ($v[4]) { $entry = "$entry largeop"; }
     if ($v[5]) { $entry = "$entry movablelimits"; }
     if ($v[6]) { $entry = "$entry stretchy"; }
     if ($v[7]) { $entry = "$entry separator"; }
     if ($v[8]) { $entry = "$entry accent"; }
     if ($v[9]) { $entry = "$entry fence"; }
     if ($v[10]) { $entry = "$entry symmetric"; }
+    if ($v[15]) { $entry = "$entry mirrorable"; }
     return $entry;
 }
 
 sub completeCommon {
     # helper to add key and private data to generateCommon
     my($entry, $key, @v_moz, @v_wg) = @_;
     
     $entry = "$key = $entry";