There seems to be no difference in the types of questions in each of these tags. At the very least, these need to be merged.
But they are extremely ambiguous and mean many different things, so perhaps something else needs to be done with them. They can't really be used by themselves, and don't add much value when they are applied. I think we should delete both of them.
There are some existing tags that cover some of the common uses more precisely. But even some of these, like htmlelement, seem fairly useless. xmlelement is supposed to be for the .NET object, but it's misused a lot. These might need deleting as well.