admin_action_-1

See hook in action

See this hook used in plugins:

Select Pluginregenerate-thumbnails.3.0.2regenerate-thumbnails.3.1.0regenerate-thumbnails.3.1.1regenerate-thumbnails.3.1.2regenerate-thumbnails.3.1.3regenerate-thumbnails.3.1.4regenerate-thumbnails.3.1.5regenerate-thumbnails.3.1.6