/**
 * Callback function for the 'webmention_reaction_overlay' filter.
 *
 * @param bool $true 
 * @return bool The filtered value.
 */
function my_webmention_reaction_overlay_callback( bool $true ) {
    // Your code here.
    return $true;
}
add_filter( 'webmention_reaction_overlay', 'my_webmention_reaction_overlay_callback' );

apply_filters( 'webmention_reaction_overlay', true )