From Joomla! Documentation

A registered bot account. Edits by an account with this set will not appear by default in Recent changes; this is intended for mass imports of data without flooding human edits from view. (To show bot edits, either click the "Show bots" link on the Special:Recentchanges page, or append &hidebots=0 directly to the page URL, or like this on Joomla! Documentation.)

Bots used by server admins[edit]

Delete page script
bulk deletion of pages
Maintenance script
as the name implies, performs maintenance tasks
Migration script
content migration from (old) wiki

Bots used by users[edit]

Pending accounts: