Need to keep XML mime types for TextEditor plugin (designer depends on that in the database).

src/plugins/texteditor/TextEditor.mimetypes.xml

@@ -5,4 +5,13 @@
         <sub-class-of type="application/octet-stream"/>
         <glob pattern="*.txt"/>
     </mime-type>
+    <mime-type type="application/xml">
+        <sub-class-of type="text/plain"/>
+        <comment>XML document</comment>
+        <glob pattern="*.xml"/>
+        <glob pattern="*.xsl"/>
+        <glob pattern="*.xslt"/>
+        <glob pattern="*.xbl"/>
+        <alias type="text/xml"/>
+    </mime-type>
 </mime-info>