This functionality works in a similar way for articles, files, news and feedback, even though the example given here is for articles.
This brings up a list of all custom fields for articles (or files/news/feedback)
This brings up a list of all articles with that particular custom field value.
Bulk actions available depend on your user access.
For example if your privilege does not allow you to delete items, or allows you to only delete articles that you have created, then there is no 'Delete' action in the list of options. If your privilege does not allow you to update items, or allows you to only update items you have created, then this menu will not be available for you at all.