These are admin-bot accounts that were desysopped when the operation of the bot was discontinued (or for other reasons, when specified). Requests for the bot to be resysopped should be discussed at the bureaucrats' noticeboard (subject to a 24-hour wait period).
Each of these former administrator accounts were desysopped when it became clear that the account was being used by someone other than the Wikipedian associated with the account. The account is sometimes blocked in this process as well. An administrator desysopped for being compromised can only regain adminship after the account is sufficiently proven to not be compromised and a bureaucrat agrees to re-grant adminship.
These are administrators who were desysopped in response to concerns of misuse. Except for early cases in the project history, decisions to revoke adminship have been made or ratified by the Arbitration Committee, or the admin recall process. Adminship to these users is typically only returnable through a request for adminship or another condition set by the Arbitration Committee. Those administrators who resigned while a case was pending are listed as resigned, with a note linking to their related ArbCom case.
These administrators were desysopped for inactivity per Wikipedia's procedure for desysopping inactive administrators (after two years of continual inactivity, they are considered long-term inactive).Inactive administrators were desysopped for being inactive for over a year (defined as making "no edits or administrative actions for at least 12 months" or "fewer than 100 edits made in the last five years"). Former administrators desysopped this way may request their rights be restored by a bureaucrat at any time (subject to a 24-hour wait period to evaluate the circumstances in which they were desysopped).
These accounts have been desysopped, but the same Wikipedian is now an administrator using a separate account. These do not include simple renames of accounts, but rather the use of another account entirely that started a new timeline of edits.
These administrators voluntarily relinquished their adminship (some of these cases, though nominally by user request, are not entirely voluntary). Many of these users requested that their adminship be revoked either because they were no longer active at Wikipedia, because they were chiefly interested in editorial contributions rather than technical administration, or because they wished to focus on other Wikimedia projects. However, some administrators resigned in recognition of the community's dissatisfaction with their activities. Former administrators who resigned their adminship in good standing may be reinstated at the discretion of any bureaucrat after a 24-hour wait period to evaluate the circumstances in which they were desysopped. Administrators who resigned under controversial circumstances must reapply for adminship by the usual means. Unless otherwise specified by the Arbitration Committee, the determination of whether "controversial circumstances" existed is left to the discretion of the bureaucrats.
These were temporary administrators for various reasons, which are noted below. Adminship was granted to them for a predefined time period.
Election: These former admins were given sysop status to allow them to edit the Wikimedia Board elections page.
Employee: These former admins were given sysop status as an employee of Bomis or the Wikimedia Foundation.
Function: These former admins were given sysop status for the purpose of doing a function such as renaming a user, moving a page, or another administrative activity.
Testing: These former admins were given sysop status for testing purposes.
Mistake These former admins were given sysop status by mistake.
These former administrators exercised their right to vanish and relinquished their administrator tools. It is understood that once an editor has requested their right to vanish that they are not returning to Wikipedia (under normal circumstances). If the editor returned to editing, their current name is listed along with their contributions and administrative logs from the past. However, if the administrator has decided to stay vanished, their contributions and administrative logs are not linked here.