WordPress at a glance
action is not described

install_plugins_pre_upload action-hook . WP 1.0

This action is documented in wp-admin/plugin-install.php

Usage

add_action( 'install_plugins_pre_upload', 'action_function_name_2311' );
function action_function_name_2311(){
	// action...
}

Where the hook is called

In file: /wp-admin/plugin-install.php
install_plugins_pre_upload
wp-admin/plugin-install.php 78
do_action( 'install_plugins_pre_upload' );

Where in WP core the hook is used

Usage not found!