diff --git a/epub33/common/js/biblio.js b/epub33/common/js/biblio.js
index f307b9e55..0dc625d0a 100644
--- a/epub33/common/js/biblio.js
+++ b/epub33/common/js/biblio.js
@@ -387,6 +387,14 @@ var biblio = {
     "US-ASCII": {
       "title": ""Coded Character Set - 7-bit American Standard Code for Information Interchange", ANSI X3.4, 1986."
     },
+    "WebP-Container": {
+      "title": "WebP Container Specification",
+      "href": "https://developers.google.com/speed/webp/docs/riff_container"
+    },
+    "WebP-LB": {
+      "title": "WebP Lossless Bitstream Specification",
+      "href": "https://developers.google.com/speed/webp/docs/webp_lossless_bitstream_specification"
+    },
     "W3CProcess": {
       "title": "W3C Process Document",
       "href": "https://www.w3.org/Consortium/Process/"
diff --git a/epub33/core/index.html b/epub33/core/index.html
index a5ac24189..981d9f7a1 100644
--- a/epub33/core/index.html
+++ b/epub33/core/index.html
@@ -692,10 +692,8 @@ <h5>Supported Media Types</h5>
 								<p>If more than one media type is listed, the first one is the preferred media type. The
 									preferred media type is strongly encouraged for all new EPUB Publications.</p>
 							</li>
-
 							<li><strong>Content Type Definition</strong>—The specification to which the given Core Media
 								Type Resource has to conform.</li>
-
 							<li><strong>Applies to</strong>—The Publication Resource type(s) that the Media Type and
 								Content Type Definition applies to.</li>
 						</ul>
@@ -719,7 +717,6 @@ <h5>Supported Media Types</h5>
 									<td> [[!GIF]] </td>
 									<td>GIF Images</td>
 								</tr>
-
 								<tr>
 									<td id="cmt-jpeg">
 										<code>image/jpeg</code>
@@ -743,7 +740,13 @@ <h5>Supported Media Types</h5>
 									</td>
 									<td>SVG documents</td>
 								</tr>
-
+								<tr>
+									<td id="cmt-webp">
+										<code>image/webp</code>
+									</td>
+									<td> [[!WebP-Container]], [[!WebP-LB]] </td>
+									<td>WebP Images</td>
+								</tr>
 
 								<tr>
 									<th colspan="3" id="cmt-grp-audio" class="tbl-group">Audio</th>
@@ -895,6 +898,11 @@ <h5>Supported Media Types</h5>
 								will monitor support for OPUS in iOS, and may remove OPUS as a core media type if the
 								level of support is inadequate.</p>
 						</div>
+						<div class="issue" data-number="1344">
+							<p>WebP is currently not defined in a stable specification and its media type has not been
+								registered with IANA. Apple also only supports WebP on macOS 11. The working group will
+								continue to monitor these issues.</p>
+						</div>
 					</section>
 
 					<section id="sec-foreign-restrictions">
@@ -7837,9 +7845,15 @@ <h2>Allowed External Identifiers</h2>
 					<tr>
 						<td>
 							<ul class="flat">
-								<li><code>application/mathml+xml</code></li>
-								<li><code>application/mathml-presentation+xml</code></li>
-								<li><code>application/mathml-content+xml</code></li>
+								<li>
+									<code>application/mathml+xml</code>
+								</li>
+								<li>
+									<code>application/mathml-presentation+xml</code>
+								</li>
+								<li>
+									<code>application/mathml-content+xml</code>
+								</li>
 							</ul>
 						</td>
 						<td>
@@ -7850,7 +7864,9 @@ <h2>Allowed External Identifiers</h2>
 						</td>
 					</tr>
 					<tr>
-						<td><code>application/svg+xml</code></td>
+						<td>
+							<code>application/svg+xml</code>
+						</td>
 						<td>
 							<code>-//W3C//DTD SVG 1.1//EN</code>
 						</td>
@@ -8945,6 +8961,8 @@ <h3>Substantive changes since <a href="https://www.w3.org/publishing/epub/epub-s
 					3.2</a></h3>
 
 				<ul>
+					<li>6-Nov-2020: Added WebP to the <a href="#cmt-grp-image">image core media types</a>. See <a
+							href="https://github.com/w3c/publ-epub-revision/issues/1344">issue 1344</a>.</li>
 					<li>6-Nov-2020: A <a href="#app-identifiers-allowed">restricted set of external identifiers</a> are
 						now allowed in publication resources. <a href="#sec-xml-constraints">References to external
 							entities</a> from the internal DTD subset remain restricted, however. See <a