what does 3chr 3e in html mean

1
2    <hr style="height:2px;border-width:0;color:gray;background-color:gray"> 

1<hr> <!--   it represents a horizontal line break, in HTML4.0 we use <hr>, 
2            in XHTML1.0 we use <hr/>,  in HTML5(which is the current version of 
3            HTML) we can use both <hr> and <hr/>    
4       -->

1 <p>HTML is a language for describing web pages.....</p>
2
3<!--the hr tag stands for horizontal rule and will make a line across your page at that point-->
4 <hr>
5
6 <p>CSS defines how to display HTML elements.....</p>