This element is used to remove any HTML tags and coding within the content area – but only those outside of < BODY > tags. Content within < BODY > tags will be preserved with full HTML coding.
(Animated GIF - Click image to enlarge)
Copy and paste the page source HTML into the content area and select the element from the right-hand list. Any HTML tags (and the < BODY > tags themselves) will be immediately removed, but HTML within the < BODY > area will be left as is.
You can also use this Toolbar button as a shortcut: