Nginx rewrite rules when WordPress core files are in a subfolder

nginx-wp-in-subfolder.rewrite.conf

# Files are physically in `wp` subfolder but we'd like to serve requests /
# Goes inside server { } block

if (!-e $request_filename) {
  # Add trailing slash to */wp-admin requests.
  rewrite /wp-admin$ $scheme://$host$request_uri/ permanent;

  # WordPress in a subdirectory rewrite rules
  rewrite ^/([_0-9a-zA-Z-]+/)?(wp-.*|xmlrpc.php) /wp/$2 break;
}