diff --git a/schema/html5/common.rnc b/schema/html5/common.rnc
index 59a5e1404..2a134398d 100644
--- a/schema/html5/common.rnc
+++ b/schema/html5/common.rnc
@@ -211,6 +211,11 @@ common.attrs.other =
 			w:string "autofocus" | w:string ""
 		}
 
+	common.attrs.blocking = 
+		attribute blocking {
+			list { w:string "render" }
+		}
+
 	common.attrs.nonce =
 		attribute nonce {
 			string
diff --git a/schema/html5/core-scripting.rnc b/schema/html5/core-scripting.rnc
index 69ec1c856..ac43aad0b 100644
--- a/schema/html5/core-scripting.rnc
+++ b/schema/html5/core-scripting.rnc
@@ -33,6 +33,7 @@ datatypes w = "http://whattf.org/datatype-draft"
 		&	script.attrs.language? # restricted in Schematron
 		&	script.attrs.integrity?
 		&	embedded.content.attrs.crossorigin?
+		&	common.attrs.blocking?
 		&	referrerpolicy?
 		)
 		script.attrs.src =
diff --git a/schema/html5/meta.rnc b/schema/html5/meta.rnc
index ef075a2ac..6c7033419 100644
--- a/schema/html5/meta.rnc
+++ b/schema/html5/meta.rnc
@@ -166,6 +166,7 @@ datatypes w = "http://whattf.org/datatype-draft"
 		&	link.attrs.imagesizes?
 		#	link.attrs.title included in common.attrs
 		&	embedded.content.attrs.crossorigin?
+		&	common.attrs.blocking?
 		&	common.attrs.aria.role.link?
 		)
 		link.attrs.href =
@@ -253,6 +254,7 @@ datatypes w = "http://whattf.org/datatype-draft"
 		(	common.attrs
 		&	style.attrs.type?
 		&	style.attrs.media?
+		&	common.attrs.blocking?
 		#	style.attrs.title included in common.attrs
 		)
 		style.attrs.type =
diff --git a/src/nu/validator/checker/schematronequiv/Assertions.java b/src/nu/validator/checker/schematronequiv/Assertions.java
index dd965168b..737178034 100644
--- a/src/nu/validator/checker/schematronequiv/Assertions.java
+++ b/src/nu/validator/checker/schematronequiv/Assertions.java
@@ -3166,6 +3166,18 @@ else if ("bdo" == localName && atts.getIndex("", "dir") < 0) {
                             + " \u201Cprerender\u201D, or"
                             + " \u201Cstylesheet\u201D.");
                 }
+                if (atts.getIndex("", "blocking") > -1
+                        && (atts.getIndex("", "rel") == -1
+                        || !(relList.contains("modulepreload")
+                            || relList.contains("preload")
+                            || relList.contains("stylesheet")))) {
+                    err("A \u201Clink\u201D element with a"
+                                + " \u201Cblocking\u201D attribute must have a"
+                                + " \u201Crel\u201D attribute whose value is"
+                                + " \u201Cmodulepreload\u201D,"
+                                + " \u201Cpreload\u201D, or"
+                                + " \u201Cstylesheet\u201D.");
+                }
             }
 
             // microdata