Manual:$wgEnotifMaxRecips

Email notification (Enotif) settings: $wgEnotifMaxRecips
Maximum number of users to mail at once when using impersonal mail.
Introduced in version:1.11.0 (r21897)
Removed in version:Still in use
Allowed values:(integer)
Default value:500

Details

Maximum number of users to mail at once when using impersonal mail. Should match the limit on your mail server.