https://bugs.freedesktop.org/show_bug.cgi?id=8170
Index: freedesktop.org.xml.in
===================================================================
--- freedesktop.org.xml.in.orig
+++ freedesktop.org.xml.in
@@ -3014,6 +3014,10 @@ command to generate the output files.
     <_comment>MacPaint Bitmap image</_comment>
     <glob pattern="*.pntg"/>
   </mime-type>
+  <mime-type type="image/x-macpaint">
+    <_comment>MacPaint Bitmap image</_comment>
+    <glob pattern="*.pntg"/>
+  </mime-type>
   <mime-type type="image/x-msod">
     <_comment>Office drawing</_comment>
     <glob pattern="*.msod"/>