WordPress at a glance
function is not described

strip_shortcode_tag() WP 3.3.0

Strips a shortcode tag based on RegEx matches against post content.

No Hooks.

Return

String/false. The content stripped of the tag, otherwise false.

Usage

strip_shortcode_tag( $m );
$m(array) (required)
RegEx matches against post content.

Code of strip shortcode tag: wp-includes/shortcodes.php WP 5.2.1

<?php
function strip_shortcode_tag( $m ) {
	// allow [[foo]] syntax for escaping a tag
	if ( $m[1] == '[' && $m[6] == ']' ) {
		return substr( $m[0], 1, -1 );
	}

	return $m[1] . $m[6];
}