These editors are for when Markdown just doesn't cut it. They are highly configured versions of TinyMCE. To get the code, just click on the 'source code' button (the last button in the toolbar) and copy and paste.
Please note, when marking a header cell, some additional styling was added which helps to distinguish them from the other cells as there is otherwise no specific styling for them. That styling (i.e. the green line) will not appear in production.