To translate characters to and from their HTML entities.
åäö -> HTML - translates characters to HTML entities.
HTML -> åäö - translates HTML entities to characters.
The characters which are translated are all that you find in the "Small Chars" and "Capital Chars" menus (except eth, thorn and y´) plus the Spanish ¡ and ¿.
<>& -> HTML - translates the characters <>& to their HTML entities.
HTML -> <>& - translates them back again.
If some text is selected, the characters are translated within the selection, otherwise they are translated in the whole document.