Update Placeholder in FacetWP Field

// Update placeholder in Max GPM "max" field
add_filter( 'facetwp_facet_html', function( $output, $params ) {
	if ( 'product_max_gpm_inputs' == $params['facet']['name'] ) { // change facet name to the name of your facet
		$output = str_replace( 'placeholder="Min"', 'placeholder="Min GPM"', $output );
	}
	return $output;
}, 10, 2 );