I guess it's not perfectly compatible. https://www.w3.org/Bugs/Public/show_bug.cgi?id=22008

zcorpan · zcorpan · commit bdff30f09521 · 2013-05-13T17:27:47.000+02:00
diff --git a/Overview.html b/Overview.html
@@ -282,7 +282,7 @@ <h3 id="development-model"><span class="secno">1.5 </span>Development Model</h3>
     <h2 id="syntax"><span class="secno">2 </span>Syntax</h2>
 
     <p>HTML defines a syntax, referred to as "the HTML syntax", that is
-    compatible with HTML4 and XHTML1 documents published on the
+    mostly compatible with HTML4 and XHTML1 documents published on the
     Web, but is not compatible with the more esoteric SGML features of
     HTML4, such as
     <a href="http://www.w3.org/TR/1999/REC-html401-19991224/appendix/notes.html#h-B.3.6">processing instructions</a>
@@ -3234,6 +3234,7 @@ <h2 class="no-num" id="acknowledgments">Acknowledgments</h2>
     James Graham,
     Jens Meiert,
     Jeremy Keith,
+    Jukka K. Korpela,
     Jürgen Jeka,
     Krijn Hoetmer,
     Leif Halvard Silli,
diff --git a/Overview.src.html b/Overview.src.html
@@ -254,7 +254,7 @@ <h3 id="development-model">Development Model</h3>
     <h2 id="syntax">Syntax</h2>
 
     <p>HTML defines a syntax, referred to as "the HTML syntax", that is
-    compatible with HTML4 and XHTML1 documents published on the
+    mostly compatible with HTML4 and XHTML1 documents published on the
     Web, but is not compatible with the more esoteric SGML features of
     HTML4, such as
     <a href="http://www.w3.org/TR/1999/REC-html401-19991224/appendix/notes.html#h-B.3.6">processing instructions</a>
@@ -3437,6 +3437,7 @@ <h2 class="no-num" id="acknowledgments">Acknowledgments</h2>
     James Graham,
     Jens Meiert,
     Jeremy Keith,
+    Jukka K. Korpela,
     J&uuml;rgen Jeka,
     Krijn Hoetmer,
     Leif Halvard Silli,
diff --git a/Overview.whatwg.html b/Overview.whatwg.html
@@ -227,7 +227,7 @@ <h3 id="development-model"><span class="secno">1.5 </span>Development Model</h3>
     <h2 id="syntax"><span class="secno">2 </span>Syntax</h2>
 
     <p>HTML defines a syntax, referred to as "the HTML syntax", that is
-    compatible with HTML4 and XHTML1 documents published on the
+    mostly compatible with HTML4 and XHTML1 documents published on the
     Web, but is not compatible with the more esoteric SGML features of
     HTML4, such as
     <a href="http://www.w3.org/TR/1999/REC-html401-19991224/appendix/notes.html#h-B.3.6">processing instructions</a>
@@ -3179,6 +3179,7 @@ <h2 class="no-num" id="acknowledgments">Acknowledgments</h2>
     James Graham,
     Jens Meiert,
     Jeremy Keith,
+    Jukka K. Korpela,
     Jürgen Jeka,
     Krijn Hoetmer,
     Leif Halvard Silli,
