The keyboard shortcuts dialog can be opened via the help menu in the bottom right corner of the tldraw component. It can be customized by providing a KeyboardShortcutsDialog component to the Tldraw component's components prop. If you provide null, then that component will be hidden instead.

import {
	DefaultKeyboardShortcutsDialog,
	DefaultKeyboardShortcutsDialogContent,
	TLComponents,
	TLUiKeyboardShortcutsDialogProps,
	Tldraw,
	TldrawUiMenuItem,
} from 'tldraw'
import 'tldraw/tldraw.css'

function CustomKeyboardShortcutsDialog(props: TLUiKeyboardShortcutsDialogProps) {
	return (
		<DefaultKeyboardShortcutsDialog {...props}>
			<div style={{ backgroundColor: 'thistle' }}>
				<TldrawUiMenuItem
					id="like-my-posts"
					label="Like my posts"
					icon="external-link"
					readonlyOk
					kbd=":)"
					onSelect={() => {
						window.open('https://x.com/tldraw', '_blank')
					}}
				/>
			</div>
			<DefaultKeyboardShortcutsDialogContent />
		</DefaultKeyboardShortcutsDialog>
	)
}

const components: TLComponents = {
	KeyboardShortcutsDialog: CustomKeyboardShortcutsDialog,
}

export default function CustomKeyboardShortcutsDialogExample() {
	return (
		<div className="tldraw__editor">
			<Tldraw components={components} />
		</div>
	)
}

Custom help menuCustom main menu