title: Firefox for Android add-on is disabled in Nightly?
body: <p>I developed a very basic Firefox add-on that uses the <code>page-mod</code> module, but I can't get it to work on Firefox for Android (Nightly). It works with Desktop Firefox.<br>
  The add-on was pushed correctly to my testing device using <code>jpm-mobile</code>, as it shows up in the <code>about:addons</code> list, however it is disabled. The "enable" button is also grayed out.<br>
  I verified that the <code>xpinstall.signatures.required</code> setting in <code>about:config</code> is set to false, so that can't be it. What else am I missing?</p>