Source

File: wp-includes/Requests/IRI.php

protected function set_fragment($ifragment) {
		if ($ifragment === null) {
			$this->ifragment = null;
		}
		else {
			$this->ifragment = $this->replace_invalid_with_pct_encoding($ifragment, '!$&\'()*+,;=:@/?');
			$this->scheme_normalization();
		}
		return true;
	}