The earliest dates back to early 2015.
Usually in projects that accept outside contributions a pull request is open for a short amount of time.
Within a few days it would be reviewed by someone in charge of the related area with one of three answers:
1. This is a good idea and well implemented, we'll pull and close.
2. This is a bad idea and does not fit with the plans, close the request.
3. This is a good idea but the implementation falls short. Improve the code in these ways and update the pull request.
There are usually discussions with all of these responses, and if there is consensus reached any one of these answers can change. If there is no further activity after a period of time on a request for improvement in implementation, the request is closed to keep the request queue tidy.
What triggered these musings is a pull request I submitted a month or so ago. There was a short discussion, then nothing. There's another pull request I'm very interested in having in the firmware. It has also been sitting there for a month with no discussion at all.
Is there a process to get a pull request evaluated?
I'm not whining "Hurry up and pull my code!" Any one of the three variants of answers are better than silence.
I'm a big boy, saying no won't hurt my feelings , In my 30+ years professionally developing code I've heard a lot of noes!