Backlinks are those links linking back to the current page. In DokuWiki you can see a list of pages linking to the current document by clicking at the Backlinks button in pagetools at the right side. If your wiki layout does not have this button you can find backlinks by appending
?do=backlink to the page URL. (In the previous default DokuWiki template you could reach the backlinks by clicking the page name at the top)
To speed up backlink searching the metadata index is used. Some plugins are also adding information about links they are dynamically creating to the index so you might or might not find links that are dynamically created (e.g. in a navigation).
A page with no backlink is called an orphan. It means that, as there is no link to it, no one can see it. However, it still can be accessed if you type its URL, or through the search engine, or even via the index feature. There is also a plugin for displaying orphaned pages available.
You can disable backlinks altogether via the configuration manager (see disableactions).
In order to remove the link of the pagename you have to edit the
lib/tpl/default/main.php of the old default DokuWiki template and replace the following:
<div class="pagename"> [[<?php tpl_link(wl($ID,'do=backlink'),tpl_pagetitle($ID,true),'title="'.$lang['btn_backlink'].'"')?>]] </div>