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.
They are unused, since there is no C++ code that touches
these settings. See the discussion in PR 9152, which is
a PR that adds a lot more Android-specific settings.
I moved it from the main settings screen to the in-game menu
in PR 8439 so that it could be changed while a game is running,
but now that the main settings can be accessed while a game is
running, there's no reason to not put it in the main settings.
https://bugs.dolphin-emu.org/issues/12067
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.)
