The former is deprecated and pretty much all modern drivers
support VK_EXT_debug_utils.
Android drivers dont support it. On those drivers,
we use the implementation provided by the validation layers.
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.