virtual-page.php

<?php

/**
 * Add virtual page on WordPress hierarchy
 * @link https://metabox.io/how-to-create-a-virtual-page-in-wordpress/
 */
 
add_filter( 'generate_rewrite_rules', function ( $wp_rewrite ){
    $wp_rewrite->rules = array_merge(
        ['example/(\w+)/?$' => 'index.php?exp=$matches[1]'],
        $wp_rewrite->rules
    );
} );

add_filter( 'query_vars', function( $query_vars ){
    $query_vars[] = 'exp';
    return $query_vars;
} );

add_action( 'template_redirect', function(){
    $exp = get_query_var( 'exp' );
    if ( $exp ) {
        include plugin_dir_path( __FILE__ ) . 'templates/example.php';
        die;
    }
} );