ACF Location rules for Multisite

acf-location-rules.php

<?php 
// Display specific ACF groups on selected sites only for Multisite. 
if ( is_multisite() ) :
	add_filter( 'acf/location/rule_types', 'acf_location_rule_type_multisite' );
	add_filter( 'acf/location/rule_values/site',  'acf_location_rule_values_multisites' );
	add_filter( 'acf/location/rule_match/site', 'acf_location_rules_match_site', 10, 3 );
endif;

function acf_location_type_multisite( $choices ) {
	
	$choices['Multisite']['site'] = 'Site';
	return $choices;
	
}

function acf_location_values_multisites( $choices ) {

	$choices ['all'] = 'All';
	$sites           = get_sites();

	foreach( $sites as $site ) {
		$choices[ get_object_vars( $site )['blog_id'] ] = get_object_vars( $site )['path'];
	}

	// if on subdomains.
	//foreach( $sites as $site ) {
    //	
	//	$name = get_blog_details( [ 'blog_id' => $site->blog_id ] )->blogname;
//
    //	$choices[ get_object_vars( $site )['blog_id'] ] = $name;
	//}
					
	return $choices;
}

function acf_location_rules_match_site( $match, $rule, $options ) {
	
	$current_site  = get_current_blog_id();
	$selected_site = (int) $rule['value'];

	if ( '==' === $rule['operator'] ) :
	
		$match = ( $current_site == $selected_site );
	
	elseif ( '!=' === $rule['operator'] ) :
	
		$match = ( $current_site !== $selected_site );
	
	endif;

	return $match;
}