Pages not found and Wordfence

Hello
I use Wordfence 1.0.1 and check each day the live traffic
I see many queries with this URL :
wp-content/plugins/wordpress-list-articles/css/admin.css?ver=4.1.1
Wordfence signals this in “pages not found”
My problem is that these queries seem to be genrated by myself with my IP or by others users or by IP considered as hackers
I have personaly never generate this query.

This file doesn’t exist in my folder

How this query is generated ?
Thank you for help
Guy