With our component now working on the customer's My Account page, let's go ahead and add it to the checkout's Review & Payments step as well.
By tapping into the checkout_index_index layout handle, and nesting our component under the desired children element, we can easily add it to the checkout page. We do so with the <MODULE_DIR>/view/frontend/layout/checkout_index_index.xml file, as follows:
<page>
<body>
<referenceBlock name="checkout.root">
<arguments>
<argument name="jsLayout" xsi:type="array">
<item name="components" xsi:type="array">
<item name="checkout" xsi:type="array">
<item name="children" xsi:type="array">
<item name="steps"...
