Please note that main.inc.php, which should be called by index.php or main.page, does
the following:

unset($_REQUEST);
unset($_GET);
unset($_POST);

So, you must use a Sanitizer to get those input vars!!!
...in your input file:
use \bs_tts\use_io as IO;
...
    $required_post_string_field = new IO();
    $required_post_string_field->input_type = INPUTS::post;
    $required_post_string_field->field_filter = FIELD_FILTER::raw_string;
    $required_post_string_field->escape_html = HTML_FLAG::escape;
    $required_post_string_field->validation_rule = 'required';
    $required_post_string_field->use_db_filter = DB_FILTER::OFF;
    $required_post_string_field->skip_the_db = false;
return [
            'name' => $required_post_string_field,
            'address' => $required_post_string_field,
];

...After that, in your output file, you will pass in the input data of type IO:
use \bs_tts\safer_io as SafeIO;
...
            $safer_html = [];
            $errors = [];
            foreach(SafeIO::html_escape_and_sanitize($input) as $html) {
                $key = $html['name'] ?? "";
                $safer_html[$key] = $html['html'];

                if (\bs_tts\common::get_count($html['errors'])) {
                    $errors[$key] = $html['errors'][$key];
                }
            }
...
Alternatively; use the built in PHP filter_input function.

Likewise, if not using sanitize... then for all HTML output use 
    \bs_tts\safer_io::h(...) to escape it.