Source

File: wp-includes/comment.php

function wp_get_current_commenter() {
	// Cookies should already be sanitized.

	$comment_author = '';
	if ( isset( $_COOKIE[ 'comment_author_' . COOKIEHASH ] ) ) {
		$comment_author = $_COOKIE[ 'comment_author_' . COOKIEHASH ];
	}

	$comment_author_email = '';
	if ( isset( $_COOKIE[ 'comment_author_email_' . COOKIEHASH ] ) ) {
		$comment_author_email = $_COOKIE[ 'comment_author_email_' . COOKIEHASH ];
	}

	$comment_author_url = '';
	if ( isset( $_COOKIE[ 'comment_author_url_' . COOKIEHASH ] ) ) {
		$comment_author_url = $_COOKIE[ 'comment_author_url_' . COOKIEHASH ];
	}

	/**
	 * Filters the current commenter's name, email, and URL.
	 *
	 * @since 3.1.0
	 *
	 * @param array $comment_author_data {
	 *     An array of current commenter variables.
	 *
	 *     @type string $comment_author       The name of the current commenter, or an empty string.
	 *     @type string $comment_author_email The email address of the current commenter, or an empty string.
	 *     @type string $comment_author_url   The URL address of the current commenter, or an empty string.
	 * }
	 */
	return apply_filters( 'wp_get_current_commenter', compact( 'comment_author', 'comment_author_email', 'comment_author_url' ) );
}