I have noticed that a lot of wikis (including some WMF wikis) assign temporary rights. Meaning that somone with the capability to do so assigns a user flags with the intent of removing them after a set period of time. However, some smaller wikis forget to remove the flags or nobody happens to be available to remove the flags, therefore ruining the concept of "temporary rights". What I propose is that a function be added to the MediaWiki core to allow Bureaucrats (or whoever assigns flags on the wiki) to set a specific time which when reached will trigger the automatic removal of rights. I also think a setting should be added (such as $wgTemporaryUserrights or similar) to allow wikis to opt in or opt out of this feature.