FacetWP – change Number Range facet “Number”, “Min” and “Max” labels

<?php

// Add to your (child) theme's functions.php

add_filter( 'gettext', function( $translated_text, $text, $domain ) {
    if ( 'fwp-front' == $domain ) {
        if ( 'Number' == $translated_text ) {
            $translated_text = 'Number (translated)';
        }
        elseif ( 'Min' == $translated_text ) {
            $translated_text = 'Min (translated)';
        }
        elseif ( 'Max' == $translated_text ) {
            $translated_text = 'Max (translated)';
        }
    }
    return $translated_text;
}, 10, 3 );