Implement hook_help()

+    switch ($route_name) {
+        case 'help.page.big_pipe_override':
+        $output = '<h3>' . t('About Big pipe override') . '</h3>';
+        $output .= '<p>' . t("This module is meant for development purposes.") . '</p>';
+        // Add a link to the Drupal.org project.
+        $output .= '<p>';
+        $output .= t('Visit the <a href=":project_link">Big pipe override project page</a> on Drupal.org for more information.',
+          [
+            ':project_link' => 'https://www.drupal.org/project/big_pipe_override',
+          ]
+        );
+        $output .= '</p>';
+        return $output;
+    }
+}

This module is meant for development purposes. is not sufficient as help. The link to the project link is useless, once the module has been installed. It would be better to give more information, preferably information that users have not already read from the project page.

Kindly Review: merge request !6

+        $output = '<h3>' . t('About Big Pipe Override') . '</h3>';

I would just use About. For the rest, it gives the essential information that help at least to use the module. People who wonder why the module does not seem to work will notice from the help they need to add a line to a file.

+ $output .= '<p><code>' . t('$settings["big_pipe_override_enabled"] = TRUE;') . '

';

Code cannot be translated. I would rather use a placeholder for the code and use that placeholder in a translatable sentence. This also avoids that translators would accidentally translate TRUE with VERO, for example (which is the Italian for true).

@apaderno updated, as per your suggestion