Editorial: move incubations to the README

Author: christianliebel

README.md

@@ -4,6 +4,7 @@ the [Web Applications Working Group](https://www.w3.org/2019/webapps/).
 ## Useful links
 * [Explainer](https://github.com/w3c/manifest/blob/gh-pages/explainer.md)
 * [The Web Application Manifest specification](https://www.w3.org/TR/appmanifest/)
+* [Manifest incubations](https://github.com/WICG/manifest-incubations)
 * [App Information supplement](https://github.com/w3c/manifest-app-info)
 * [Use cases and requirements](https://w3c-webmob.github.io/installable-webapps/)
 * [The Web Applications WG homepage](https://www.w3.org/2019/webapps/)

index.html

@@ -3264,45 +3264,6 @@ <h3>
         </section>
       </section>
     </section>
-    <section class="appendix informative">
-      <h2 id="incubations">
-        Incubations
-      </h2>
-      <p>
-        Extensions to this specification are being incubated in parallel by the
-        Web Community, some of which are shipping in multiple browsers. If two
-        or more browser engines end up supporting an incubated feature, then
-        those features will become part of this specification in the future -
-        allowing them to become a standard the Web Platform:
-      </p>
-      <dl>
-        <dt>
-          `BeforeInstallPrompt` and `window.onappinstalled` event
-        </dt>
-        <dd>
-          The `BeforeInstallPrompt` event and `window.onappinstalled` event
-          were originally part of this specification. However, they were
-          <a href="https://github.com/w3c/manifest/pull/836">removed from the
-          specification</a> because they did not have support from two or more
-          implementers. You can now find them in the <a href=
-          "https://github.com/WICG/manifest-incubations">`BeforeInstallPrompt`
-          event and `window.onappinstalled` repository</a> at the <a href=
-          "https://wicg.io"><abbr title=
-          "Web Incubator Community Group">WICG</abbr></a>.
-        </dd>
-        <dt>
-          `share_target` member
-        </dt>
-        <dd>
-          The `share_target` member registers a web application as "target" for
-          share actions (e.g., for sharing a text, a URL, or a file). The
-          `share_target` member is part of the <a href=
-          "https://wicg.github.io/web-share-target/">Web Share Target</a>
-          specification, being incubated at the <a href=
-          "https://wicg.io">WICG</a>.
-        </dd>
-      </dl>
-    </section>
     <section class="appendix informative">
       <h2>
         Application Information