This is a mark with e id.
will output [object HTMLUnknownElement] without the patch, and [object HTMLSpanElement @ 0x... (native @ 0x...)] with the patch.
All marks have a yellow background.
This example shows how the mark element can be used to bring attention to a particular part of a quotation:
Consider the following quote:
Look around and you will find, no-one's realy colour blind.
As we can tell from the spelling of the word, the person writing this quote is clearly not American.
Another example of the mark element is highlighting parts of a document that are matching some search string. If someone looked at a document, and the server knew that the user was searching for the word "kitten", then the server might return the document with one paragraph modified as follows:
I also have some kittens who are visiting me these days. They're really cute. I think they like my garden! Maybe I should adopt a kitten.
More examples in HTML 5 Draft Recommendation.