They seem to be problematic since the comment in the header comes
before the <?xml version="1.0"?> tag and seems to make fontconfig not
be able to properly process the file.
** Fontconfig
:PROPERTIES:
-:header-args+: :tangle ~/.config/fontconfig/fonts.conf
+:header-args+: :tangle ~/.config/fontconfig/fonts.conf :comments none
:END:
#+begin_src xml