How to build a module which calls a JS file on one certain node? There’s one site (A) which via an API of one other Drupal site (B) gets an already rendered views block displayed on one node - finally with hook_menu() and hook_block_view(). So now I have that node (/stuff) here with it’s views rows and views fields containers.

Since these things really have nothing to do with (B) (where I also don’t have access to) I want to build a module (button) on (A) which calls a JS to manipulate the DOM only on /stuff. Which hooks and syntax will I need?
I think you're looking for something like hook_page_alter() + drupal_add_js(), e.g.

function MYMODULE_page_alter(&amp;$page) {
  // Check that we're on the right page.
  if (arg(0) == 'stuff' &amp;&amp; !arg(1)) {
    // And add some JS.
    drupal_add_js(drupal_get_path('module', 'MYMODULE') . '/MYMODULE.js');
  }
}


This could also be done in hook_preprocess_page(), hook_init(), and probably a bunch of other places. I chose hook_page_alter() at random out of those, each should be equally effective.