In July 2021 Oracle updated their documentation URLs, so now you must be logged into NetSuite in order to view the convenient PDFs. See the list of all documentation here:
https://docs.oracle.com/en/cloud/saas/netsuite/ns-online-help/preface_3710621755.html
SS2.0 API
https://system.netsuite.com/app/help/helpcenter.nl?fid=SuiteScript20API.pdf
If you’re looking to learn more about SuiteScripting please feel free to reach out to me, robert@netsuiteguide.com