The start-tags of all elements that could occur after point. The name of the element is read from the mini-buffer with completion on valid elements. C-c RET Split the current element at point. If repeated, the containing element will be split before the beginning of then current element.
Typical use is to start a new paragraph element when inside a paragraph.
Otherwise the command will operate on the element after point. The attribute name will be read with completion. If the attribute has a token list as declared value the attribute value will also be read with completion. Emacs will prompt for the markup to insert using the menu line as selector. The menu contains sub menus with tags and with entities, some other markup and a user defined section.