Canonical Ltd

Canonical Ltd.[4] is a privately held computer software company based in London, England. It was founded and funded by South African entrepreneur Mark Shuttleworth to market commercial support and related services for Ubuntu and related projects. Canonical employs staff in more than 70 countries and maintains offices in London, Austin, Boston, Shanghai, Beijing, Taipei, Tokyo and the Isle of Man. https://en.wikipedia.org/wiki/Canonical_(company)

I've seen multiple stories about them having a ridiculous hiring process. Such as https://dustri.org/b/my-experience-with-canonicals-interview-process.html