Depending on a users group permissions they see a different enter bug page. For users in the canconfirm group or higher they see the standard enter bug page with the following text at the top:
Consider using the Bugzilla Helper instead of this form. Before reporting a bug, make sure you've read our bug writing guidelines and double checked that your bug hasn't already been reported. Consult our list of most frequently reported bugs and search through descriptions of previously reported bugs.
It has a link to the duplicates.cgi page which shows most duplicate bugs for a given product. This page is very old and needs some work to be more useful.
The guided bug page is displayed to users who are new to Bugzilla and do not have canconfirm permissions. It has a duplicate search form built in that lets users first search for their issue before filing a new report.
All employees and a lot of contributors will already have canconfirm permissions and will see the normal bug entry page. I am going to update the duplicate text that is there currently to be separate from the other text and be more prominent. I am going to also do some tweaks to the current duplicates.cgi page to make it more useful. This will include passing along the product name by default and allow also pick a version to search for duplicates. Currently the form shows most duplicated bugs for a product across all versions and this gives some really old bugs at the top which are of no use to the current releases.