Can Windows 10 Extended Security Updates be downloaded from the Microsoft Update Catalog and installed manually on a PC that is not enrolled in the ESU program and does not use a Microsoft account? The updates appear to be listed in the catalog, so I'm wondering whether installation checks the device's ESU eligibility or whether anyone has successfully installed them this way.
2 Answers
We tested this, and the updates would not install on a device that wasn’t enrolled in the ESU program.
No, they can’t simply be installed from the catalog on an ineligible machine. The installation process checks whether the device has the required ESU eligibility, so downloading the package alone isn’t enough.

Do you know whether the installer performs that eligibility check directly, or whether it fails because the required ESU licensing components aren’t present?