Achoo — iOS Safari Extension to view HTML Source
Quickly view the HTML for a given page in Safari on iOS/iPadOS 15. Customizable, beautiful, easy to use, and you can tweak the page too!
When tapping the “Edit” button it activates
contenteditable on the page. Costs $0.99.
If you don’t want to buy this extension, or are not using Safari as your browser, you can always use online tools such as View Source to check the (server-rendered) markup.