Yandex (and ClickHouse) does some really, really cool technical stuff.

I like that a lot of the stuff they write about and open-source has a fairly strong focus on efficiency + performance. I also find the supporting docs (those that detail the problem space, how it solves the problem, etc) quite well written and often a lot more comprehensible than docs from other mainstream tech companies (MS docs are the worst, followed by Google).

I’m not sure why this is the case though, is it a different development culture? Different project management culture (provisions time for documentation?) something else?

For example, both Go and .NET are very well written engineering achievements with thorough documentation. Many, many other deeply influential projects have also been absorbed by the Apache Foundation or other FOSS initiatives.

Furthermore, every software megacorp has boat loads of teams working on hundreds even thousands (!) of different open source projects. The quality naturally varies.

Let me pick two more esoteric projects as a point of comparison.

Yandex Odyssey [0] an advanced multi-threaded PostgreSQL connection pooler and request router. Figuring out how exactly and when to use this is not quite clear. There is no "getting started" guide for this package. There is barely any explanation for how it works or what it does.

pg_auto_failover [1] run by Citus (owned by Microsoft) monitors and manages automated failover for a Postgres cluster. This repo even has diagrams explaining the workflow and complete instructions.

Frankly, it's unreal just how much code is open nowadays especially from the giants.

Visual Studio, for example, had been under lockdown for 20 years. Now Visual Studio Code is being developed in the open and has extremely thorough documentation that walks developers through the entire build process in painstaking detail.[2] This is a blazing fast editor written in JavaScript of all things! Or consider TypeScript, an incredible engineering feat. There is an entire repo dedicated to engineering notes on how the compiler works with links to interesting feature contributions and a video! [3]

I'm only picking Microsoft here as the primary example since you dumped on them the hardest.

*No other industry does this. It is absolutely wild how much copyleft influenced software culture.*

[0]: https://github.com/yandex/odyssey

[1]: https://github.com/citusdata/pg_auto_failover

[2]: https://github.com/microsoft/vscode/wiki/How-to-Contribute

[3]: https://github.com/microsoft/TypeScript-Compiler-Notes/