Stored procedures starting dt_

I have SQL Server 6.5  in Production .
Off late I could see some stored procedure got created in the production database .
There are total 18 Stored procedure of that type , all prefixed with dt_ .
For ex.
dt_addtosourcecontrol          
dt_adduserobject              
dt_adduserobject_vcs          
dt_checkinobject              
dt_checkoutobject
etc .

Can any body suggest me where these objects have come from , any other tool etc .

Thanks.