Need to Register “swarmify” Protocol after Elementor 3.19 Update

After updating to Elementor 3.19, the Elementor SmartVideo widget no longer displays Swarmify videos where the Source is set to “Another Source” containing a “swarmify://” URL (or in our case an ACF Custom Field containing a “swarmify://” URL).

This is caused by an Elementor update that has switched to using esc_url() for all URL Control fields (reported in their changelog as “Fix: Added better output escaping to URL controls”): https://github.com/elementor/elementor/commit/cf292a5659511f0ed8d3223f4eaba1aecbe0493d

To remedy this issue, one should register “swarmify” as an allowed protocol. I would suggest that this be integrated into the official Swarmify plugin, but for now this snippet does the trick:

add_filter( 'kses_allowed_protocols' , function ( $protocols ) {
  $protocols[] = 'swarmify';
  return $protocols;
});