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.

Since all queues are FIFO data structures, the name wasn't informative
as to why you'd use it over a normal queue. I originally thought it had
something to do with the hardware graphics FIFO.

This renames it using the common acronym SPSC, which stands for
single-producer single-consumer, and is most commonly used to talk about
lock-free data structures, both of which this is.