Editorial edits from buglist

sections/acknowledgements.include

@@ -4,10 +4,10 @@
   Thanks to Tim Berners-Lee for inventing HTML, without which none of this would exist, Dan Connolly,
   the many who worked to standardise HTML over the last couple of decades or so, and the many more who
   worked on ideas subsequently incorporated into HTML.
-  
+
   For inestimable work, and the drive to keep HTML up to date, particular thanks are due to Ian Hickson,
   and the other editors of the WHATWG: Anne van Kesteren, Domenic Denicola, Philip Jägenstedt,
-  Simon Pieters. 
+  Simon Pieters.
 
   With apologies to people who have undeservedly not been named, thanks to
 
@@ -244,7 +244,7 @@
   Eliot Graff,
   Elisabeth Robson,
   Elizabeth Castro,
-  Elliott Regan, 
+  Elliott Regan,
   Elliott Sprehn,
   Elliotte Harold,
   Eric Carlson,
@@ -571,6 +571,7 @@
   Peter Beverloo,
   Peter Karlsson,
   Peter Kasting,
+  Peter Lemieux,
   Peter Moulder,
   Peter Occil,
   Peter Stark,
@@ -665,6 +666,7 @@
   Stefan Håkansson,
   Stefan Haustein,
   Stefan Santesson,
+  Stefan Schumacher,
   Stefan Weiss,
   Steffen Meschkat,
   Stephen Ma,

sections/infrastructure.include

@@ -41,14 +41,14 @@
   <a>XML MIME type</a>.
 
   The term <dfn lt="XHTML document|XHTML documents">XHTML document</dfn> is used to refer to both <a>documents</a> in the
-  <a>XML document</a> mode that contains element nodes in the <a>HTML namespace</a>, and byte
+  <a>XML document</a> mode that contain element nodes in the <a>HTML namespace</a>, and byte
   streams labeled with an <a>XML MIME type</a> that contain elements from the <a>HTML namespace</a>,
   depending on context.
 
   <hr />
 
-  For simplicity, terms such as <dfn>shown</dfn>, <dfn>displayed</dfn>, and <dfn>visible</dfn> might
-  sometimes be used when referring to the way a document is rendered to the user. These terms are
+  For simplicity, terms such as <dfn>shown</dfn>, <dfn>displayed</dfn>, and <dfn>visible</dfn> are
+  used (sometimes) when referring to the way a document is rendered to the user. These terms are
   not meant to imply a visual medium; they must be considered to apply to other media in equivalent
   ways.
 
@@ -212,10 +212,10 @@
 
 <h4 id="plugin-content-handlers"><code>Plugin</code> Content Handlers</h4>
 
-  The term <dfn lt="plugin|plugins">plugin</dfn> refers to a user-agent defined set of content handlers used by the user
-  agent that can take part in the user agent's rendering of a {{Document}} object, but that
-  neither act as <a>child browsing contexts</a> of the {{Document}} nor introduce any
-  {{Node}} objects to the {{Document}}'s DOM.
+  The term <dfn lt="plugin|plugins">plugin</dfn> refers to a user-agent defined set of content
+  handlers that can be used by the user agent. The content handlers can take part in the user
+  agent's rendering of a {{Document}} object, but that neither act as <a>child browsing contexts</a>
+  of the {{Document}} nor introduce any {{Node}} objects to the {{Document}}'s DOM.
 
   Typically such content handlers are provided by third parties, though a user agent can also
   designate built-in content handlers as <a>plugins</a>.
@@ -254,8 +254,8 @@
     <p class="warning">
       Browsers should take extreme care when interacting with external content intended for
       <a>plugins</a>. When third-party software is run with the same privileges as the user agent
-      itself, vulnerabilities in the third-party software become as dangerous as those in the user
-      agent.
+      itself, vulnerabilities in the third-party software become as dangerous as if they were
+      vulnerabilities of the user agent itself.
     </p>
 
     Since different users having different sets of <a>plugins</a> provides a fingerprinting vector
@@ -521,9 +521,8 @@
         the author of the document or section. However, since an authoring tool is likely unable to
         determine the difference, an authoring tool is exempt from that requirement. This does not
         mean, though, that authoring tools can use <{address}> elements for any block of
-        italics text (for instance); it just means that the authoring tool doesn't have to verify
-        that when the user uses a tool for inserting contact information for a section, that the
-        user really is doing that and not inserting something else instead.
+        italics text (for instance); it just means that the authoring tool doesn't have to verify,
+        if a user inserts contact information for a section or something else.
       </p>
 
       <p class="note">

sections/introduction.include

@@ -1045,7 +1045,7 @@
         or an <{h2}> heading:</p>
 
         <pre class="bad" highlight="html">&lt;h2>Contact details&lt;/h1></pre>
-    
+
   : Cases that are likely to be typos
   :: When a user makes a simple typo, it is helpful if the error can be caught early, as this can
       save the author a lot of debugging time. This specification therefore usually considers it
@@ -1062,8 +1062,8 @@
       harmless features are disallowed.
 
       <p class="example">
-        For example, "attributes" in end tags are ignored currently, but they are invalid, in case a
-        future change to the language makes use of that syntax feature without conflicting with
+        For example, "attributes" in end tags are currently invalid and ignored. A future change to
+        the language may make use of this syntax feature and can do so without conflicting with
         already-deployed (and valid!) content.
       </p>
 

sections/semantics-embedded-content.include

@@ -310,7 +310,7 @@ was an English <a href="/wiki/Music_hall">music hall</a> singer, ...
       To specify dimensions that the user agent can use before having downloaded the image,
       CSS can be used.
 
-      <pre class="css">
+      <pre highlight="css">
         img { width: 300px; height: 300px }
         @media (min-width: 32em) { img { width: 500px; height:300px } }
         @media (min-width: 45em) { img { width: 700px; height:400px } }
@@ -476,7 +476,7 @@ was an English &lt;a href="/wiki/Music_hall"&gt;music hall&lt;/a&gt; singer, ...
   must begin with one or more <a>space characters</a>.
 
   If the <code>srcset</code> attribute has any
-  <a>image candidate strings</a> using a <i>width descriptor</i>,
+  <a>image candidate strings</a> using a <a>width descriptor</a>,
   the <dfn element-attr for="source"><code>sizes</code></dfn> content attribute must also be present,
   and the value must be a <a>valid source size list</a>.
 
@@ -626,10 +626,10 @@ was an English &lt;a href="/wiki/Music_hall"&gt;music hall&lt;/a&gt; singer, ...
 
     <ul>
 
-      <li>A <i>width descriptor</i>, consisting of:
+      <li>A <dfn>width descriptor</dfn>, consisting of:
       a <a>space character</a>,
       a <a>valid non-negative integer</a> giving a number greater than zero
-      representing the <i>width descriptor</i> value,
+      representing the <dfn>width descriptor value</dfn>,
       and a U+0077 LATIN SMALL LETTER W character.</li>
 
       <li>A <i>pixel density descriptor</i>, consisting of:
@@ -647,8 +647,8 @@ was an English &lt;a href="/wiki/Music_hall"&gt;music hall&lt;/a&gt; singer, ...
   </ol>
 
   There must not be an <a>image candidate string</a> for an element that
-  has the same <i>width descriptor</i> value as another
-  <a>image candidate string</a>'s <i>width descriptor</i> value for the same element.
+  has the same <a>width descriptor value</a> as another
+  <a>image candidate string</a>'s <a>width descriptor value</a> for the same element.
 
   There must not be an <a>image candidate string</a> for an element that
   has the same <i>pixel density descriptor</i> value as another
@@ -660,14 +660,14 @@ was an English &lt;a href="/wiki/Music_hall"&gt;music hall&lt;/a&gt; singer, ...
   If a <{source}> element has a <code>sizes</code> attribute present
   or an <{img}> element has a <code>sizes</code> attribute present,
   all <a>image candidate strings</a> for that
-  element must have the <i>width descriptor</i> specified.
+  element must have the <a>width descriptor</a> specified.
 
   If an <a>image candidate string</a> for a <code>source</code> or
-  <{img}> element has the <i>width descriptor</i> specified, all other
+  <{img}> element has the <a>width descriptor</a> specified, all other
   <a>image candidate strings</a> for that element must also
-  have the <i>width descriptor</i> specified.
+  have the <a>width descriptor</a> specified.
 
-  The specified width in an <a>image candidate string</a>'s <i>width descriptor</i>
+  The specified width in an <a>image candidate string</a>'s <a>width descriptor</a>
   must match the <a>intrinsic width</a> in the resource given by the
   <a>image candidate string</a>'s URL, if it has an <a>intrinsic width</a>.
 
@@ -1326,7 +1326,7 @@ was an English &lt;a href="/wiki/Music_hall"&gt;music hall&lt;/a&gt; singer, ...
   and a <a>source size</a>.
 
   An <dfn>image source</dfn> is a <a for="url">URL</a>,
-  and optionally either a density descriptor, or a width descriptor.
+  and optionally either a density descriptor, or a <a>width descriptor</a>.
 
   A <dfn>source size</dfn> is a <code>&lt;source-size-value&gt;</code>.
   When a <a>source size</a> has a unit relative to the viewport,
@@ -1400,7 +1400,7 @@ was an English &lt;a href="/wiki/Music_hall"&gt;music hall&lt;/a&gt; singer, ...
         whose value is not the empty string
         and <var>source set</var> does not contain an
         <a>image source</a> with a density descriptor value of 1,
-        and no <a>image source</a> with a width descriptor,
+        and no <a>image source</a> with a <a>width descriptor</a>,
         append <var>child</var>'s <code>src</code> attribute value to <var>source set</var>.</li>
 
         <li><a>Normalize the source densities</a> of <var>source set</var>.</li>
@@ -1812,7 +1812,7 @@ was an English &lt;a href="/wiki/Music_hall"&gt;music hall&lt;/a&gt; singer, ...
   </p>
 
   An <a>image source</a> can have a density descriptor,
-  a width descriptor,
+  a <a>width descriptor</a>,
   or no descriptor at all accompanying its URL.
   Normalizing a <a>source set</a> gives every <a>image source</a> a density descriptor.
 
@@ -1834,9 +1834,9 @@ was an English &lt;a href="/wiki/Music_hall"&gt;music hall&lt;/a&gt; singer, ...
 
       <li>
 
-      Otherwise, if the <a>image source</a> has a width descriptor,
-      replace the width descriptor with a density descriptor
-      with a value of the width descriptor divided by the <a>source size</a>
+      Otherwise, if the <a>image source</a> has a <a>width descriptor</a>,
+      replace the <a>width descriptor</a> with a density descriptor
+      with a value of the <a>width descriptor</a> divided by the <a>source size</a>
       and a unit of <code>x</code>.
 
       <p class="note">
@@ -3090,26 +3090,27 @@ My &lt;img src="heart.png" alt="heart"&gt; breaks.
   Use an empty <code>alt</code> attribute when an icon is supplemental to
   text conveying the same meaning.
 
-    <div class="example">
-  In this example, we have a link pointing to a site's home page, the link contains a
-  house icon image and the text "home". The image has an empty <code>alt</code> text.
-  Where images are used in this way, it would also be appropriate to add the image using CSS
+  <div class="example">
+    In this example, we have a link pointing to a site's home page, the link contains a
+    house icon image and the text "home". The image has an empty <code>alt</code> text.
 
-  <img src="images/home.png" alt="A house icon next to the word 'home'." width="100" height="38" />
+    <img src="images/home.png" alt="A house icon next to the word 'home'." width="100" height="38" />
 
-  <pre highlight="html">
-  &lt;a href="home.html"&gt;&lt;img src="home.gif" width="15" height="15" alt=""&gt;Home&lt;/a&gt;
+    <pre highlight="html">
+      &lt;a href="home.html"&gt;&lt;img src="home.gif" width="15" height="15" alt=""&gt;Home&lt;/a&gt;
     </pre>
 
-  <pre highlight="css">
-  #home:before
-  {
-  content: url(home.png);
-  }
+    Where images are used in this way, it would also be appropriate to add the image using CSS.
 
-  &lt;a href="home.html" id="home"&gt;Home&lt;/a&gt;
+    <pre highlight="css">
+      #home:before
+      {
+      content: url(home.png);
+      }
+
+      &lt;a href="home.html" id="home"&gt;Home&lt;/a&gt;
     </pre>
-    </div>
+  </div>
 
     <div class="example">
   In this example, there is a warning message, with a warning icon. The word "Warning!" is in emphasized
@@ -5927,6 +5928,7 @@ zero or more <{track}> elements, then
 
   </div>
 
+  <div class="note">
   If the element's <a>track URL</a> identifies a <a>WebVTT</a> resource, and the
   element's <code>kind</code> attribute is not in the <a state for="track">Metadata</a> state, then the <a>WebVTT</a> file must be
   a <a>WebVTT file using cue text</a>. [[WEBVTT]]
@@ -5935,6 +5937,7 @@ zero or more <{track}> elements, then
   and the element's <code>kind</code> attribute is in the <a>chapters</a> state, then the <a>WebVTT</a> file must be
   both a <a>WebVTT file using chapter title text</a> and a <a>WebVTT file using only nested
   cues</a>. [[WEBVTT]]
+  </div>
 
   The <dfn element-attr for="track"><code>srclang</code></dfn> attribute gives the language of
   the text track data. The value must be a valid BCP 47 language tag. This attribute must be present
@@ -13589,8 +13592,8 @@ red:89
 
 <h4 id="sec-dimension-attributes"><dfn>Dimension attributes</dfn></h4>
 
-  <span class="impl"><strong>Author requirements</strong>:</span> The 
-  <dfn element-attr for="media,img,iframe,embed,object,video,input"><code>width</code></dfn> and 
+  <span class="impl"><strong>Author requirements</strong>:</span> The
+  <dfn element-attr for="media,img,iframe,embed,object,video,input"><code>width</code></dfn> and
   <dfn element-attr for="media,img,iframe,embed,object,video,input"><code>height</code></dfn> attributes on <{img}>, <{iframe}>,
   <{embed}>, <{object}>, <{video}>, and, when their <code>type</code> attribute is in the <a element-state for="input">image button</a> state, <{input}> elements may be
   specified to give the dimensions of the visual content of the element (the width and height