How to remove the tagline from the HTML ?

by

Ah, figured it out.

In /wp-content/themes/twentyeleven/header.php, you can comment out this:

// Add the blog description for the home/front page.
$site_description = get_bloginfo( 'description', 'display' );
if ( $site_description && ( is_home() || is_front_page() ) )
    echo " | $site_description";

Then the blog tagline won’t be added for the front page.