That method allow configure Animated PNG even:
> ikiwiki.sphynkx.org.ua
+----
+Sphynkx
+
+> Typically sites that use animated pngs (ugh!) as favicons just call it
+> `favicon.ico`. It's not as if (most) web servers and browsers trust
+> the filename extension to mean anything anyway. And using favicon.ico
+> makes it more likely to work with old browsers that just always look for
+> that. --[[Joey]]