--- a/toolkit/content/license.html
+++ b/toolkit/content/license.html
@@ -181,16 +181,17 @@
       <li><a href="about:license#same-file">same-file License</a></li>
       <li><a href="about:license#sctp">SCTP Licenses</a></li>
       <li><a href="about:license#skia">Skia License</a></li>
       <li><a href="about:license#snappy">Snappy License</a></li>
       <li><a href="about:license#sprintf.js">sprintf.js License</a></li>
       <li><a href="about:license#strsim">strsim License</a></li>
       <li><a href="about:license#sunsoft">SunSoft License</a></li>
       <li><a href="about:license#superfasthash">SuperFastHash License</a></li>
+      <li><a href="about:license#synstructure">synstructure License</a></li>
       <li><a href="about:license#unicode">Unicode License</a></li>
       <li><a href="about:license#ucal">University of California License</a></li>
       <li><a href="about:license#hunspell-en-US">US English Spellchecking Dictionary Licenses</a></li>
       <li><a href="about:license#v8">V8 License</a></li>
       <li><a href="about:license#validator">Validator License</a></li>
       <li><a href="about:license#vtune">VTune License</a></li>
       <li><a href="about:license#webrtc">WebRTC License</a></li>
       <li><a href="about:license#x264">x264 License</a></li>
@@ -6567,16 +6568,48 @@ LOSS OF USE, DATA, OR PROFITS; OR BUSINE
 ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF THIS
 SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 </pre>
 
 
     <hr>
 
+    <h1><a id="synstructure"></a>synstructure License</h1>
+
+    <p>This license applies to files in the directory
+    <code>third_party/rust/synstructure</code>.</p>
+
+<pre>
+The MIT License (MIT)
+
+Copyright (c) 2016 Michael Layzell
+
+Permission is hereby granted, free of charge, to any person obtaining a copy
+of this software and associated documentation files (the "Software"), to deal
+in the Software without restriction, including without limitation the rights
+to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
+copies of the Software, and to permit persons to whom the Software is
+furnished to do so, subject to the following conditions:
+
+The above copyright notice and this permission notice shall be included in
+all copies or substantial portions of the Software.
+
+THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
+IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
+FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL THE
+AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
+LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
+OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
+THE SOFTWARE.
+</pre>
+
+
+    <hr>
+
     <h1><a id="unicode"></a>Unicode License</h1>
 
     <p>This license applies to files in the <code>intl/icu</code>
     and <code>intl/tzdata</code> directories and certain files in
     the <code>js/src/vm</code> directory.</p>
     </p>
 
 <pre>