I think most are missing that this is a code review + loyalty review.
For sure a software engineer from Tesla, or even a manager, can get an idea of how valuable/productive a coder is without fully understanding the code in detail. How many PRs? What does the code do? How was it reviewed? What value does it bring to stakeholders (users, business revenue)? Sure enough this way you can get a rough idea of how much work somebody does and if it is of any importance.
The loyalty part is in the timing: 30-60 days. A period with a lot of uncertainty for Twitter employees. The Musk takeover in the air but even if that would not follow through, there were already severe job cuts in the pipeline by Twitter's board.
If under those conditions you kept your head down and kept coding like a stoic, then you're a keeper.
Number of PR's means very little with overall productivity. It's a vanity metric.
100%
I made 400 last year. It was two fixes across many files owned by many different teams.
Ideally it would have been two. Sometimes playing the politics game is required.
To be fair Twitter has a monorepo.
Mostly. Many of their foundational components e.g. Finagle are open sourced and in separate repos.
Are those actually the upstream repositories, though? And is it known how they interact with them?
Google has Copybara [1], which allows portions of a monorepo to live outside as an entirely separate repository without the need for things like Git submodules. It supports synchronization of histories, pull requests, path and file transformations, etc.
In that sense, something like Copybara would allow them to, relatively, easily open source those bits, receive outside commits, and then sync the changes back to the monorepo.