What is an SEO ready WordPress theme?

Hello everyone,

I hope that everyone come across this technological yet web buzzword in WordPress. That is, “SEO Ready Themes”. When we install WordPress, default theme works as it should and output page-title, description, generator, ref’s, previous and next links. I hope they are the part of header.php file elements which go with wp_head().

So, I need someone who can help to clarify it a bit more than a cheesy two line answer.
Peace.