Manual:$wgSessionHandler/de-formal

<translate> Cookies</translate>: $wgSessionHandler
Used to set PHP's session.save_handler.
<translate> Introduced in version:</translate>	1.16.0 (r49370)
<translate> Deprecated in version:</translate>	1.27.0 (Gerrit change 267737; git #2257fe42)
<translate> Removed in version:</translate>	1.33.0 (Gerrit change 489405; git #a38fe6cd)
<translate> Allowed values:</translate>	(string) or null
<translate> Default value:</translate>	null (1.18-1.32) 'files' (1.16-1.17)
<translate> Other settings:</translate> <translate> Alphabetical</translate> | <translate> By function</translate>

Details

This is used for setting PHP's session.save_handler. In practice, you will almost never need to change this ever. Other options might be 'user' or 'session_mysql'.

Setting to null skips setting this entirely (which might be useful if you're doing cross-application sessions, see bug 11381).