Allow custom attributes to html elements - CookieYes | GDPR Cookie Consent (https://wordpress.org/plugins/cookie-law-info/)

functions.php

<?php //do not copy this line

add_filter( 'wp_kses_allowed_html', 'wt_cli_allow_custom_attributes', 20, 2);
function wt_cli_allow_custom_attributes($tags, $context) {
	$cli_allowed = array(
		'data-*' => true,
	);
	if( isset($tags['a']) && is_array($tags['a']) ) {
		$tags['a'] = array_merge($tags['a'], $cli_allowed);
	}

	return $tags;
}