What does this mean in wordpress? Easy question

Question

Im digging wordpress and started to look into templates to be specific blank themes/frameworks for making custom themes. I found "HTML5Blank" and was going through source code and found something i do not understand.

<h1 class="htittle"><?php _e( 'News', 'html5blank' ); ?></h1>

What is the part 'html5blank' doing? Its repeating everywhere. Its not in the comments so its got to be some part of wordpress codex but i dont know even what to google. More examples :

<h1><?php _e( 'About ', 'html5blank' ); echo get_the_author() ; ?></h1>

again there is... , 'html5blank' ) . Why is that here? Even more examples

<span class="comments"><?php comments_popup_link( __( 'Leave your thoughts', 'html5blank' ), __( '1 Comment', 'html5blank' ), __( '% Comments', 'html5blank' )); ?></span>

Here its repeating more times, i cant figure it out.

Then i went through the sourc of another blank framework called "Bones". Again same thing

<p><?php _e( 'This is the error message in the archive.php template.', 'bonestheme' ); ?></p>  

,'bonestheme' ?? what is this doing?

<h1><?php _e( 'Oops, Post Not Found!', 'bonestheme' ); ?></h1>

Answer 1

It's the text domain, used for translation. When you run something like this:

<?php _e( 'Hello World', 'html5blank' ) ?>

...WordPress will attempt to find the translated string in the loaded MO file for HTML5 Blank:

load_theme_textdomain( 'html5blank', 'path/to/language.mo' );