diff --git a/src/components/propertylist.css b/src/components/propertylist.css
index c71c304..f1b2f32 100644
--- a/src/components/propertylist.css
+++ b/src/components/propertylist.css
@@ -7,7 +7,7 @@
 	--ck-inspector-color-property-list-property-name: #D0363F;
 	--ck-inspector-color-property-list-property-value-true: green;
 	--ck-inspector-color-property-list-property-value-false: red;
-	--ck-inspector-color-property-list-property-value-undefined: #888;
+	--ck-inspector-color-property-list-property-value-unknown: #888;
 	--ck-inspector-color-property-list-background: #F5F5F5;
 }
 
@@ -43,8 +43,13 @@
 			color: var(--ck-inspector-color-property-list-property-value-true);
 		}
 
-		&[value="undefined"] {
-			color: var(--ck-inspector-color-property-list-property-value-undefined);
+		&[value="undefined"],
+		&[value="function() {…}"] {
+			color: var(--ck-inspector-color-property-list-property-value-unknown);
+		}
+
+		&[value="function() {…}"] {
+			font-style: italic;
 		}
 	}
 }
diff --git a/src/components/utils.js b/src/components/utils.js
index c949ebd..9162b14 100644
--- a/src/components/utils.js
+++ b/src/components/utils.js
@@ -8,6 +8,10 @@ export function stringify( value, quotesAroundText = true ) {
 		return 'undefined';
 	}
 
+	if ( typeof value === 'function' ) {
+		return 'function() {…}';
+	}
+
 	const stringified = JSON.stringify( value );
 
 	// Note: Remove leading and trailing quotes (") from the output. By default it is:
@@ -37,6 +41,10 @@ export function uid() {
 
 export function stringifyPropertyList( list ) {
 	return list.map( ( [ name, value ] ) => {
+		if ( typeof name === 'symbol' ) {
+			name = name.toString();
+		}
+
 		return [ name, stringify( value ) ];
 	} );
 }
diff --git a/src/components/view/nodeinspector.js b/src/components/view/nodeinspector.js
index 89e9957..729d72c 100644
--- a/src/components/view/nodeinspector.js
+++ b/src/components/view/nodeinspector.js
@@ -18,6 +18,8 @@ import {
 import { stringifyPropertyList } from '../utils';
 import ObjectInspector from '../objectinspector';
 
+const DOCS_URL_PREFIX = 'https://ckeditor.com/docs/ckeditor5/latest/api/module_engine_view';
+
 class NodeInspector extends Component {
 	editorEventObserverConfig( props ) {
 		return {
@@ -61,6 +63,11 @@ class NodeInspector extends Component {
 					url: info.url,
 					items: info.properties
 				},
+				{
+					name: 'Custom Properties',
+					url: `${ DOCS_URL_PREFIX }_element-Element.html#function-getCustomProperty`,
+					items: info.customProperties
+				}
 			]}
 		/>;
 	}
@@ -84,29 +91,30 @@ class NodeInspector extends Component {
 		const info = {
 			editorNode: node,
 			properties: [],
-			attributes: []
+			attributes: [],
+			customProperties: []
 		};
 
 		if ( isViewElement( node ) ) {
 			if ( isViewRoot( node ) ) {
 				info.type = 'RootEditableElement';
 				info.name = node.rootName;
-				info.url = 'https://ckeditor.com/docs/ckeditor5/latest/api/module_engine_view_rooteditableelement-RootEditableElement.html';
+				info.url = `${ DOCS_URL_PREFIX }_rooteditableelement-RootEditableElement.html`;
 			} else {
 				info.name = node.name;
 
 				if ( isViewAttributeElement( node ) ) {
 					info.type = 'AttributeElement';
-					info.url = 'https://ckeditor.com/docs/ckeditor5/latest/api/module_engine_view_attributeelement-AttributeElement.html';
+					info.url = `${ DOCS_URL_PREFIX }_attributeelement-AttributeElement.html`;
 				} else if ( isViewEmptyElement( node ) ) {
 					info.type = 'EmptyElement';
-					info.url = 'https://ckeditor.com/docs/ckeditor5/latest/api/module_engine_view_emptyelement-EmptyElement.html';
+					info.url = `${ DOCS_URL_PREFIX }_emptyelement-EmptyElement.html`;
 				} else if ( isViewUiElement( node ) ) {
 					info.type = 'UIElement';
-					info.url = 'https://ckeditor.com/docs/ckeditor5/latest/api/module_engine_view_uielement-UIElement.html';
+					info.url = `${ DOCS_URL_PREFIX }_uielement-UIElement.html`;
 				} else {
 					info.type = 'ContainerElement';
-					info.url = 'https://ckeditor.com/docs/ckeditor5/latest/api/module_engine_view_containerelement-ContainerElement.html';
+					info.url = `${ DOCS_URL_PREFIX }_containerelement-ContainerElement.html`;
 				}
 			}
 
@@ -116,10 +124,11 @@ class NodeInspector extends Component {
 				[ 'isEmpty', node.isEmpty ],
 				[ 'childCount', node.childCount ],
 			);
+			info.customProperties.push( ...node.getCustomProperties() );
 		} else {
 			info.name = node.data;
 			info.type = 'Text';
-			info.url = 'https://ckeditor.com/docs/ckeditor5/latest/api/module_engine_view_text-Text.html';
+			info.url = `${ DOCS_URL_PREFIX }_text-Text.html`;
 
 			info.properties.push(
 				[ 'index', node.index ]
@@ -127,6 +136,7 @@ class NodeInspector extends Component {
 		}
 
 		info.properties = stringifyPropertyList( info.properties );
+		info.customProperties = stringifyPropertyList( info.customProperties );
 		info.attributes = stringifyPropertyList( info.attributes );
 
 		return info;
diff --git a/tests/inspector/components/utils.js b/tests/inspector/components/utils.js
index 4feee9c..b8dbf70 100644
--- a/tests/inspector/components/utils.js
+++ b/tests/inspector/components/utils.js
@@ -17,6 +17,7 @@ describe( 'Utils', () => {
 			expect( stringify( 'foo' ) ).to.equal( '"foo"' );
 			expect( stringify( [ 'a' ] ) ).to.equal( '["a"]' );
 			expect( stringify( { a: false } ) ).to.equal( '{"a":false}' );
+			expect( stringify( () => 'foo' ) ).to.equal( 'function() {…}' );
 		} );
 
 		it( 'stringifies values (no quotes around text)', () => {
@@ -25,6 +26,7 @@ describe( 'Utils', () => {
 			expect( stringify( 'foo', false ) ).to.equal( 'foo' );
 			expect( stringify( [ 'a' ], false ) ).to.equal( '["a"]' );
 			expect( stringify( { a: false }, false ) ).to.equal( '{"a":false}' );
+			expect( stringify( () => 'foo' ), false ).to.equal( 'function() {…}' );
 		} );
 	} );
 
@@ -39,9 +41,11 @@ describe( 'Utils', () => {
 			expect( stringifyPropertyList( [
 				[ 'foo', 'bar' ],
 				[ 'baz', 'qux' ],
+				[ Symbol( '42' ), 'abc' ]
 			] ) ).to.have.deep.members( [
 				[ 'foo', '"bar"' ],
 				[ 'baz', '"qux"' ],
+				[ 'Symbol(42)', '"abc"' ]
 			] );
 		} );
 	} );
diff --git a/tests/inspector/components/view/nodeinspector.js b/tests/inspector/components/view/nodeinspector.js
index 731e338..83b14c0 100644
--- a/tests/inspector/components/view/nodeinspector.js
+++ b/tests/inspector/components/view/nodeinspector.js
@@ -109,6 +109,10 @@ describe( '<ViewNodeInspector />', () => {
 		it( 'renders for a RootElement', () => {
 			editor.setData( '<p>foo</p>' );
 
+			editor.editing.view.change( writer => {
+				writer.setCustomProperty( 'foo', 'bar', editor.editing.view.document.getRoot() );
+			} );
+
 			wrapper.setProps( {
 				inspectedNode: root
 			} );
@@ -133,11 +137,23 @@ describe( '<ViewNodeInspector />', () => {
 				[ 'isEmpty', 'false' ],
 				[ 'childCount', '1' ],
 			] );
+
+			expect( lists[ 2 ].name ).to.equal( 'Custom Properties' );
+
+			const items = lists[ 2 ].items;
+			expect( items[ 0 ] ).to.have.members( [ 'Symbol(rootName)', '"main"' ] );
+			expect( items[ 1 ][ 0 ] ).to.equal( 'Symbol(document)' );
+			expect( items[ 1 ][ 1 ] ).to.match( /^{/ );
+			expect( items[ 2 ] ).to.have.members( [ 'foo', '"bar"' ] );
 		} );
 
 		it( 'renders for a ContainerElement', () => {
 			editor.setData( '<p>foo</p>' );
 
+			editor.editing.view.change( writer => {
+				writer.setCustomProperty( 'foo', 'bar', editor.editing.view.document.getRoot().getChild( 0 ) );
+			} );
+
 			wrapper.setProps( {
 				inspectedNode: root.getChild( 0 )
 			} );
@@ -157,11 +173,20 @@ describe( '<ViewNodeInspector />', () => {
 				[ 'isEmpty', 'false' ],
 				[ 'childCount', '1' ],
 			] );
+
+			expect( lists[ 2 ].name ).to.equal( 'Custom Properties' );
+			expect( lists[ 2 ].items ).to.deep.equal( [
+				[ 'foo', '"bar"' ]
+			] );
 		} );
 
 		it( 'renders for an AttributeElement', () => {
 			editor.setData( '<p><b>foo</b></p>' );
 
+			editor.editing.view.change( writer => {
+				writer.setCustomProperty( 'foo', 'bar', editor.editing.view.document.getRoot().getChild( 0 ).getChild( 0 ) );
+			} );
+
 			wrapper.setProps( {
 				inspectedNode: root.getChild( 0 ).getChild( 0 )
 			} );
@@ -181,6 +206,11 @@ describe( '<ViewNodeInspector />', () => {
 				[ 'isEmpty', 'false' ],
 				[ 'childCount', '1' ],
 			] );
+
+			expect( lists[ 2 ].name ).to.equal( 'Custom Properties' );
+			expect( lists[ 2 ].items ).to.deep.equal( [
+				[ 'foo', '"bar"' ]
+			] );
 		} );
 
 		it( 'renders for an EmptyElement', () => {
@@ -189,6 +219,7 @@ describe( '<ViewNodeInspector />', () => {
 			editor.editing.view.change( writer => {
 				const foo = writer.createEmptyElement( 'foo' );
 				writer.insert( editor.editing.view.document.selection.getFirstPosition(), foo );
+				writer.setCustomProperty( 'foo', 'bar', foo );
 			} );
 
 			wrapper.setProps( {
@@ -210,6 +241,11 @@ describe( '<ViewNodeInspector />', () => {
 				[ 'isEmpty', 'true' ],
 				[ 'childCount', '0' ],
 			] );
+
+			expect( lists[ 2 ].name ).to.equal( 'Custom Properties' );
+			expect( lists[ 2 ].items ).to.deep.equal( [
+				[ 'foo', '"bar"' ]
+			] );
 		} );
 
 		it( 'renders for an UIElement', () => {
@@ -218,6 +254,7 @@ describe( '<ViewNodeInspector />', () => {
 			editor.editing.view.change( writer => {
 				const foo = writer.createUIElement( 'foo' );
 				writer.insert( editor.editing.view.document.selection.getFirstPosition(), foo );
+				writer.setCustomProperty( 'foo', 'bar', foo );
 			} );
 
 			wrapper.setProps( {
@@ -239,6 +276,11 @@ describe( '<ViewNodeInspector />', () => {
 				[ 'isEmpty', 'true' ],
 				[ 'childCount', '0' ],
 			] );
+
+			expect( lists[ 2 ].name ).to.equal( 'Custom Properties' );
+			expect( lists[ 2 ].items ).to.deep.equal( [
+				[ 'foo', '"bar"' ]
+			] );
 		} );
 
 		it( 'renders for a Text', () => {