Mathematica files don't have a unique magic, but try to detect based on the file starting with a Mathematica-style comment as all we can do. Also add the newer Wolfram Language mimetype, which extends mathematica, with a unix  detection
<mime-type type="application/marc">
<glob pattern="*.mrc"/>
</mime-type>
+
<mime-type type="application/mathematica">
+ <_comment>Wolfram Mathematica</_comment>
<glob pattern="*.ma"/>
<glob pattern="*.nb"/>
<glob pattern="*.mb"/>
+ <!-- Note - there is no Unique Magic for Mathematica files! -->
+ <!-- Check for a Mathematica-style opening comment as our best hope... -->
+ <magic priority="50">
+ <match value="(**" type="string" offset="0"/>
+ <match value="(* " type="string" offset="0"/>
+ </magic>
+ <sub-class-of type="text/plain"/>
</mime-type>
+ <mime-type type="application/vnd.wolfram.wl">
+ <_comment>Wolfram Language</_comment>
+ <glob pattern="*.wl"/>
+ <magic priority="50">
+ <match value="#!/usr/bin/env wolframscript" type="string" offset="0"/>
+ </magic>
+ <sub-class-of type="application/mathematica"/>
+ </mime-type>
+
<mime-type type="application/mathml+xml">
<glob pattern="*.mathml"/>
</mime-type>
