Footer Copyright information

Hello,

I am really new to WP and really new to html. I hope you don’t mind I ask if it is very easy to you. I am trying to alter the copyright info of the “Attitude” theme (Since it is GNU Licenced), I went to the footer-extensions.php and I found this:

function attitude_footer_info() {
   $output = '<div class="copyright">'.__( 'Copyright &copy;', 'attitude' ).' '.'[the-year] [site-link]'.' '.__( 'Theme by:', 'attitude' ).' '.'[th-link]'.' '.__( 'Powered by:', 'attitude' ).' '.'[wp-link] '.'</div><!-- .copyright -->';
   echo do_shortcode( $output );
}

Do you know why there is a text “attitude” after every text such as ‘Theme by:’, ‘Powered by:’? It looks like a function to me calling for appropriate input, which is the information I want to change.

Besides, what does ” .__ ” mean? I haven’t seen this before? Is it a html code or specifically for WP?

Many thanks,

Gordon