Library pages are intended to be stand-alone articles on a particular topic. The quality of the individual pages varies greatly: there are stub articles, articles of notes of future clean-up, reasonable drafts, and some polished pages. The general policy is to not delete information from the Library; if something is incomplete, or even incorrect - but has potential to be to corrected and improved, then the page should remain.
Note: the above page contents is generated via a JQuery script embedded in the actual page. It pulls the page listing from the HTML table generated by MediaWiki's Special:PrefixIndex and builds a new HTML listing. View the Template:PrefixIndex template for more details.