WordPress at a glance
action is not described

parse_request action-hook . WP 2.1.0

Fires once all query variables for the current request have been parsed.

Usage

add_action( 'parse_request', 'action_function_name_1174' );
function action_function_name_1174( $this ){
	// action...
}
$this(WP)
Current WordPress environment instance (passed by reference).

Where the hook is called

WP::parse_request()
parse_request
wp-includes/class-wp.php 375
do_action_ref_array( 'parse_request', array( &$this ) );

Where the hook is used (in WP core)

wp-includes/default-filters.php 436
add_action( 'parse_request', 'rest_api_loaded' );