Manual:$wgUseEnotif

Email notification (Enotif) settings: $wgUseEnotif
Overall "use Enotif" setting
Introduced in version:1.5.0 (r9649)
Removed in version:Still in use
Allowed values:(boolean)
Default value:false (see below)

Introduced in r9649. This is the global "use Enotif or not" setting. This is configured in Setup.php to be true if either $wgEnotifWatchlist or $wgEnotifUserTalk is true.