History of user rights
Originally, only a few people ("sysops") could delete pages and block users. There was one admin password that was shared.
Eventually, individual administrator rights were assigned to specific users.
Bureaucrats eventually came as a result of an increased userbase and a corresponding need for higher-order administrative functions. People wanted to be renamed and have their bots flagged, and having to edit the database for the promotion of new admins was becoming impractical and time consuming. Thus, the bureaucrat was born and took charge of these tasks.
Tim Starling first suggested the idea of a steward in a mailing list post on March 9, 2004. In his original proposal, the role would act as a root user does on a Unix system, with the ability to assign or remove any rights on any Wikimedia wiki. In the mailing list post, he suggested that the first stewards be Angela and Mav (then Maveric149). Tim concurrently created the Developer access page at Meta.
Tim created the Stewards page at Meta suggesting a list of people who should be stewards on April 4, 2004. The list included eight names (six more than in the original mailing list post a month earlier).
CheckUser was originally named "Userip.php." It was written by Ævar Arnfjörð Bjarmason on April 17, 2005. Prior to this, sysadmins would query the database manually. On May 23, 2005, the Special page that Userip.php used was renamed from Special:Userip to Special:Espionage.
Page histories were also unalterable by anyone other than system administrators until May 2006 when the Oversight extension was created as a "temporary" hack while the revision deletion core feature was being developed. Oversight moves revisions to a parallel database table that is entirely inaccessible from the wiki software. A log is kept of oversights for transparency. Originally the log was open to the public; however in July 2006, it was made private. Only system administrators are able to reverse the oversight of an edit.
It's unclear how Jimbo Wales was originally in the developer user group (likely it was done directly from the database backend); however, on February 5, 2006, Danny made Jimbo Wales a "local steward." From 2006 to 2008, Jimbo remained the only "local steward" at the English Wikipedia. On the same day (February 5), Jimbo was given steward rights at Meta by Sj.
Having the local steward bit allowed Jimbo to add or remove any rights locally (rather than at Meta). Over the years, questions were raised about two things: (1) why did Jimbo have local steward rights; and (2) why was he the only one in the local group? A bug was filed regarding this on November 11, 2007. On the same day, Tim renamed the local steward group to "founder." The founder group allows a user to access Special:UserRights (userrights) and Special:Makesysop (makesysop).
In 2008, global groups were introduced that allow stewards to create customized user groups with various rights.
Unlike other global groups, the "steward" global group is created by the software via a script that is installed along with SUL.
- mw:Extension:Oversight as of 24 May 2006