Add a unit test and some documentation

packages/components/CHANGELOG.md

@@ -5,6 +5,7 @@
 ### Enhancements
 
 -   `InputControl`/`SelectControl`: update `height`/`min-height` to `32px` instead of `30px` to align with modern sizing scale ([#55490](https://github.com/WordPress/gutenberg/pull/55490)).
+-   `ComboboxControl`: Add `shouldFilter` prop to allow the options to be controlled and filtered externally ([#55574](https://github.com/WordPress/gutenberg/pull/55574)). 
 
 ### Bug Fix
 

packages/components/src/combobox-control/README.md

@@ -95,6 +95,14 @@ Function called when the control's search input value changes. The argument cont
 -   Type: `( value: string ) => void`
 -   Required: No
 
+#### shouldFilter
+
+Function called to determine whether the control should filter the list of displayed options based on the user input or whether it's something that is handled externally by updating the `options` prop when the `onFilterValueChange` callback is called.
+
+-   Type: `boolean`
+-	Required: No
+-	Default: `true`
+
 #### onChange
 
 Function called with the selected value changes.

packages/components/src/combobox-control/test/index.tsx

@@ -212,6 +212,34 @@ describe.each( [
 		expect( input ).toHaveValue( targetOption.label );
 	} );
 
+	it( 'should not filter the list of options if shouldFilter is false', async () => {
+		const user = await userEvent.setup();
+		const targetOption = timezones[ 0 ];
+		const onChangeSpy = jest.fn();
+		render(
+			<Component
+				options={ timezones }
+				label={ defaultLabelText }
+				onChange={ onChangeSpy }
+				shouldFilter={ false }
+			/>
+		);
+		const input = getInput( defaultLabelText );
+
+		// Pressing tab selects the input and shows the options
+		await user.tab();
+
+		// Type enough characters to ensure a predictable search result
+		await user.keyboard( 'Japan' );
+
+		// Pressing Enter/Return selects the currently focused option
+		await user.keyboard( '{Enter}' );
+
+		expect( onChangeSpy ).toHaveBeenCalledTimes( 1 );
+		expect( onChangeSpy ).toHaveBeenCalledWith( targetOption.value );
+		expect( input ).toHaveValue( targetOption.label );
+	} );
+
 	it( 'should render aria-live announcement upon selection', async () => {
 		const user = await userEvent.setup();
 		const targetOption = timezones[ 9 ];