diff --git a/wp-includes/js/dist/vendor/wp-polyfill-dom-rect.js b/wp-includes/js/dist/vendor/wp-polyfill-dom-rect.js
new file mode 100644
index 0000000000..9ed8ce994e
--- /dev/null
+++ b/wp-includes/js/dist/vendor/wp-polyfill-dom-rect.js
@@ -0,0 +1,101 @@
+
+// DOMRect
+(function (global) {
+	function number(v) {
+		return v === undefined ? 0 : Number(v);
+	}
+	
+	function different(u, v) {
+		return u !== v && !(isNaN(u) && isNaN(v));
+	}
+
+	function DOMRect(xArg, yArg, wArg, hArg) {
+		var x, y, width, height, left, right, top, bottom;
+
+		x = number(xArg);
+		y = number(yArg);
+		width = number(wArg);
+		height = number(hArg);
+
+		Object.defineProperties(this, {
+			x: {
+				get: function () { return x; },
+				set: function (newX) {
+					if (different(x, newX)) {
+						x = newX;
+						left = right = undefined;
+					}
+				},
+				enumerable: true
+			},
+			y: {
+				get: function () { return y; },
+				set: function (newY) {
+					if (different(y, newY)) {
+						y = newY;
+						top = bottom = undefined;
+					}
+				},
+				enumerable: true
+			},
+			width: {
+				get: function () { return width; },
+				set: function (newWidth) {
+					if (different(width, newWidth)) {
+						width = newWidth;
+						left = right = undefined;
+					}
+				},
+				enumerable: true
+			},
+			height: {
+				get: function () { return height; },
+				set: function (newHeight) {
+					if (different(height, newHeight)) {
+						height = newHeight;
+						top = bottom = undefined;
+					}
+				},
+				enumerable: true
+			},
+			left: {
+				get: function () {
+					if (left === undefined) {
+						left = x + Math.min(0, width);
+					}
+					return left;
+				},
+				enumerable: true
+			},
+			right: {
+				get: function () {
+					if (right === undefined) {
+						right = x + Math.max(0, width);
+					}
+					return right;
+				},
+				enumerable: true
+			},
+			top: {
+				get: function () {
+					if (top === undefined) {
+						top = y + Math.min(0, height);
+					}
+					return top;
+				},
+				enumerable: true
+			},
+			bottom: {
+				get: function () {
+					if (bottom === undefined) {
+						bottom = y + Math.max(0, height);
+					}
+					return bottom;
+				},
+				enumerable: true
+			}
+		});
+	}
+	
+	global.DOMRect = DOMRect;
+}(self));
diff --git a/wp-includes/js/dist/vendor/wp-polyfill-dom-rect.min.js b/wp-includes/js/dist/vendor/wp-polyfill-dom-rect.min.js
new file mode 100644
index 0000000000..b6af4517a5
--- /dev/null
+++ b/wp-includes/js/dist/vendor/wp-polyfill-dom-rect.min.js
@@ -0,0 +1 @@
+!function(){function d(e){return void 0===e?0:Number(e)}function g(e,n){return!(e===n||isNaN(e)&&isNaN(n))}self.DOMRect=function(e,n,t,i){var u,r,o,f,c=d(e),a=d(n),m=d(t),b=d(i);Object.defineProperties(this,{x:{get:function(){return c},set:function(e){g(c,e)&&(c=e,u=r=void 0)},enumerable:!0},y:{get:function(){return a},set:function(e){g(a,e)&&(a=e,o=f=void 0)},enumerable:!0},width:{get:function(){return m},set:function(e){g(m,e)&&(m=e,u=r=void 0)},enumerable:!0},height:{get:function(){return b},set:function(e){g(b,e)&&(b=e,o=f=void 0)},enumerable:!0},left:{get:function(){return u=void 0===u?c+Math.min(0,m):u},enumerable:!0},right:{get:function(){return r=void 0===r?c+Math.max(0,m):r},enumerable:!0},top:{get:function(){return o=void 0===o?a+Math.min(0,b):o},enumerable:!0},bottom:{get:function(){return f=void 0===f?a+Math.max(0,b):f},enumerable:!0}})}}();
\ No newline at end of file
diff --git a/wp-includes/js/dist/vendor/wp-polyfill-node-contains.js b/wp-includes/js/dist/vendor/wp-polyfill-node-contains.js
new file mode 100644
index 0000000000..c00f3bc28b
--- /dev/null
+++ b/wp-includes/js/dist/vendor/wp-polyfill-node-contains.js
@@ -0,0 +1,34 @@
+
+// Node.prototype.contains
+(function() {
+
+	function contains(node) {
+		if (!(0 in arguments)) {
+			throw new TypeError('1 argument is required');
+		}
+
+		do {
+			if (this === node) {
+				return true;
+			}
+		// eslint-disable-next-line no-cond-assign
+		} while (node = node && node.parentNode);
+
+		return false;
+	}
+
+	// IE
+	if ('HTMLElement' in self && 'contains' in HTMLElement.prototype) {
+		try {
+			delete HTMLElement.prototype.contains;
+		// eslint-disable-next-line no-empty
+		} catch (e) {}
+	}
+
+	if ('Node' in self) {
+		Node.prototype.contains = contains;
+	} else {
+		document.contains = Element.prototype.contains = contains;
+	}
+
+}());
diff --git a/wp-includes/js/dist/vendor/wp-polyfill-node-contains.min.js b/wp-includes/js/dist/vendor/wp-polyfill-node-contains.min.js
new file mode 100644
index 0000000000..35509f51f4
--- /dev/null
+++ b/wp-includes/js/dist/vendor/wp-polyfill-node-contains.min.js
@@ -0,0 +1 @@
+!function(){function e(e){if(!(0 in arguments))throw new TypeError("1 argument is required");do{if(this===e)return!0}while(e=e&&e.parentNode);return!1}if("HTMLElement"in self&&"contains"in HTMLElement.prototype)try{delete HTMLElement.prototype.contains}catch(e){}"Node"in self?Node.prototype.contains=e:document.contains=Element.prototype.contains=e}();
\ No newline at end of file
diff --git a/wp-includes/version.php b/wp-includes/version.php
index 35ffe13532..dba11a4735 100644
--- a/wp-includes/version.php
+++ b/wp-includes/version.php
@@ -13,7 +13,7 @@
  *
  * @global string $wp_version
  */
-$wp_version = '5.8-alpha-50616';
+$wp_version = '5.8-alpha-50617';
 
 /**
  * Holds the WordPress DB revision, increments when changes are made to the WordPress DB schema.