Manual:$wgExtendedLoginCookies

Authentication: $wgExtendedLoginCookies
Dictates when the extended lifetime login cookies expire.
Introduced in version:1.26.0 (Gerrit change 141248; git #16cea35d)
Removed in version:1.28.0 (Gerrit change 295551; git #04993ace)
Allowed values:(integer) or null
Default value:null

Dictates when the extended lifetime login cookies expire.

Default login cookie lifetime, in seconds. Setting $wgExtendLoginCookieExpiration to null will use $wgCookieExpiration to calculate the cookie lifetime. As with $wgCookieExpiration, 0 will make login cookies session-only.

Example edit

To make login cookies session-only, you can use:

$wgCookieExpiration = 0;