&gt;  it&#x27;s easy to polypill,<p>It may be easy from an internal implementation point of view, but from a usage point of view I disagree, unfortunately. It disallows using static html&#x2F;css only web-components which strongly goes against the grain of HTML&#x27;s intent of providing markup only documents. Granted it&#x27;s a minor use case these days, but it is important to the underlying philosophy of HTML and strongly limits the feasibility of building a static html-only _and_ modular website. Let&#x27;s say a client&#x27;s JS is disabled (via NoScript which addons.mozilla.org reports as having 2 million users). In this case it&#x27;d completely break html-only web-components for 2 million plus users, even components used primarily for CSS modularity. Unless I&#x27;m missing something with how ES2015 modules will work...? This seems like a major lack of support for any notion of custom-components and particularly of user preferences on how they view the web. Which is probably why this seems such (to me) an odd stance for the Firefox developers to take. I&#x27;ll be following the ES2015 modules to figure out if I&#x27;m missing something in this!<p>Here&#x27;s an example use case: tailoring static html based documentation with use case based theming. Depending on the clients origin and&#x2F;or browser type, it&#x27;d be trivial to redirect http html-import requests to support various themes&#x2F;clients. While technically possible without native html-imports, it&#x27;d require either JS support or dynamic rewriting of html files (essentially run-time vulcanization on the server) rather than a simple http redirect to a modular component.<p>&gt; To that end, support for a restricted subset of &lt;script type=&quot;module&quot;&gt; should land in Firefox Nightly<p>It&#x27;ll be interesting to see how ES2015 Modules and module loader spec eases the day-to-day usage of web-components. Even with polyfills Firefox seems to be difficult to coax into loading custom components -- vulcanizing the html is the only method I&#x27;ve found to be reliable. I&#x27;ll test drive the &lt;script type=&quot;module&quot;&gt; and file any bugs that I might find, thanks for the heads up! The script module should support x-tag library pretty well.