What is the purpose of the pre html tag?

The text displayed within a pre element is displayed in a fixed width and a default font. Spaces and line breaks are both displayed as typed. So text that you typed within a pre tag will be displayed exactly how you typed it.

Example:

<pre>
This is    a test within
a pre html       Tag
</pre> 

The above will ouput:

  This is  a test within
a pre html   Tag

The same text without the pre tag will display the following output:

This is a test within a pre html Tag