SPDX standardizes how source code conveys its copyright and licensing
information. See https://spdx.github.io/spdx-spec/1-rationale/ . SPDX
tags are adopted in many large projects, including things like the Linux
kernel.
Other than the controller settings and JIT debug settings,
these are the only settings which were defined in Java code
but not defined in the new config system in C++. (There are
still a lot of settings that are defined in the new config
system but not yet saveable in the new config system, though.)