Why do libraries registered in the init of the bx library work on all pages?

Question

PHP

AddEventHandler("main","OnEpilog",array("JsTestClass","OnEpilogHandler"));
class JsTestClass{
  function OnEpilogHandler(){
    
    CJSCore::RegisterExt('lib2_1', array(
  'js' => '/local/js/lib2_1/lib2_1.js',
  'css' => '/local/js/lib2_1/lib2_1.css',
  'lang' => '/local/js/lib2_1/lang/'.LANGUAGE_ID.'/lib2_1.php'
));

CJSCore::RegisterExt('bxjs2_2', array(
  'js' => '/local/js/bxjs2_2/bxjs2_2.js',
  //'css' => '/local/js/lib2_1/lib2_1.css',
  'lang' => '/local/js/bxjs2_2/lang/'.LANGUAGE_ID.'/bxjs2_2.php'

));
    //};
   //CJSCore::Init(array("bxjs2_2"));
  //CJSCore::Init(array("ajax"));
//CJSCore::Init(array('lib2_1'));
  }

};

In theory, the page should be connected in these ways.
And then the libraries should work when on these pages. But they work everywhere.
CUtil::InitJSCore(array('lib2_1'));
CJSCore::Init(array("lib2_1"))

CUtil::InitJSCore(array('bxjs2_2'));
CJSCore::Init(array("bxjs2_2"))

Answer 1

Maybe because init is connected on all pages..