Available from version 1.37.0 (Gerrit change 708537)
Use this hook to override the action name depending on request parameters.
Define function:
public static function onGetActionName( IContextSource $context, string &$action ) { ... }
Attach hook: In extension.json:
	"Hooks": {
		"GetActionName": "MediaWiki\\Extension\\MyExtension\\Hooks::onGetActionName"
Called from: File(s): actions/ActionFactory.php
Function(s): getActionName
Interface: GetActionNameHook.php

For more information about attaching hooks, see Manual:Hooks .
For examples of extensions using this hook, see Category:GetActionName extensions.