&$slotDiffRenderer: SlotDiffRenderer to change or replace.
$context: IContextSource
+'GetUserBlock': Modify the block found by the block manager. This may be a
+single block or a composite block made from multiple blocks; the original
+blocks can be seen using CompositeBlock::getOriginalBlocks()
+&$block: AbstractBlock object
+
'getUserPermissionsErrors': Add a permissions error when permissions errors are
checked for. Use instead of userCan for most cases. Return false if the user
can't do it, and populate $result with the reason in the form of
the user's current group memberships.
'UserIsBlockedFrom': Check if a user is blocked from a specific page (for
-specific block exemptions).
+specific block exemptions if a user is already blocked).
$user: User in question
$title: Title of the page in question
&$blocked: Out-param, whether or not the user is blocked from that page.