While most major Linux distributions have been supporting UEFI SecureBoot for years already in order to work nicely on modern locked-down (generally Windows pre-loaded) PCs, Debian stable releases have yet to properly support SecureBoot but that should be changing with this year’s release of 10.0 Buster…

Source: Phoronix – Debian 10 “Buster” Working To Have UEFI SecureBoot In Good Shape