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action is not described

pre-plupload-upload-ui action-hook . WP 1.0

This action is documented in wp-admin/includes/media.php

Usage

add_action( 'pre-plupload-upload-ui', 'action_function_name_7192' );
function action_function_name_7192(){
	// action...
}

Where the hook is called

wp_print_media_templates()
pre-plupload-upload-ui
media_upload_form()
pre-plupload-upload-ui
wp-includes/media-template.php 265
do_action( 'pre-plupload-upload-ui' ); // phpcs:ignore WordPress.NamingConventions.ValidHookName.UseUnderscores
wp-admin/includes/media.php 2244
do_action( 'pre-plupload-upload-ui' ); // phpcs:ignore WordPress.NamingConventions.ValidHookName.UseUnderscores

Where in WP core the hook is used WordPress

Usage not found.