Export is getting your site out of a tool in a form that works somewhere else.
Ask a builder for your site and see what you get. Wix and Squarespace have no design export at all. You can download text and images, then start over.
WordPress exports a database file. It is portable to another WordPress install, and not much else.
From Think Bright Sites you get the HTML file for each page, with your words and photos, and a README. The file renders anywhere. What does not export is our platform: the editor, chat, forms-to-records, staging and hosting. The README says what to replace them with.
Lock-in is when leaving a tool costs so much that you stay whether or not it still serves you.
A single-file HTML page keeps its words, styling and layout in one file that any browser can open.
A static site is made of finished files that a server hands out as they are, with nothing built on the fly.
A version is a saved copy of your page at one moment in time.
Paste your URL. We rebuild it, show you the match, and measure the speed. No template. No blank page. Human review from start to finish.