Add support to your plugin or theme for WordPress Personal Data Exporter (GDPR Compliancy).

plugin-privacy-user-data-eraser.php

<?php

/**
 * Register eraser for Plugin user data.
 *
 * @param array $erasers
 *
 * @return array
 */
function plugin_register_erasers( $erasers = array() ) {
	$erasers[] = array(
		'eraser_friendly_name' => __( 'User Social Accounts' ),
		'callback'               => 'plugin_user_data_eraser',
	);

	return $erasers;
}

add_filter( 'wp_privacy_personal_data_erasers', 'plugin_register_erasers' );

/**
 * Eraser for Plugin user data.
 *
 * @param     $email_address
 * @param int $page
 *
 * @return array
 */
function plugin_user_data_eraser( $email_address, $page = 1 ) {

	if ( empty( $email_address ) ) {
		return array(
			'items_removed'  => false,
			'items_retained' => false,
			'messages'       => array(),
			'done'           => true,
		);
	}

	$user         = get_user_by( 'email', $email_address );

	$messages = array();
	$items_removed  = false;
	$items_retained = false;

	if ( $user && $user->ID ) {

		// Delete their fb url
		$deleted_fb_url = delete_user_meta( $user->ID, 'facebook_url' );
		if ( $deleted_fb_url ) {
			$items_removed = true;
		} else {
			$messages[] = __( 'Your Facebook url was unable to be removed at this time.');
			$items_retained = true;
		}

		// Delete their twitter handle
		$deleted_twitter_handle = delete_user_meta( $user->ID, 'twitter_handle' );
		if ( $deleted_twitter_handle ) {
			$items_removed = true;
		} else {
			$messages[] = __( 'Your twitter url was unable to be removed at this time.');
			$items_retained = true;
		}
	}

	// Returns an array of exported items for this pass, but also a boolean whether this exporter is finished.
	//If not it will be called again with $page increased by 1.
	return array(
		'items_removed'  => $items_removed,
		'items_retained' => $items_retained,
		'messages'       => $messages,
		'done'           => true,
	);
}
plugin-privacy-user-data-exporter.php

@danieliser Mind if I make some suggestions regarding the file above?

You've got an array where you're using the same set of keys twice in the same function. That's not DRY. I think that array be could abstracted out of the function into it's own separate function. Then use the conditional to check whether $email_address is empty or not. If yes, return the configuration array; if not, keep processing.

Those checks for $deleted_fb_url and $deleted_twitter_handle can also be abstracted away into their own functions. Then call those checker functions in the main function 'plugin_user_data_eraser'. This will make your main function skinnier and easier to read.

Another point: Could you please relocate add_filter( 'wp_privacy_personal_data_erasers', 'plugin_register_erasers' ); above the callback to which it's registered? PHP doesn't care (it will parse the same regardless). But it's easier for humans to read and follow the code.