This is one of the values of open source. Sometimes it's simply a labor of love. Since you're not "on the clock" to get the work done, you, sometimes, spend a little more time to improve the result, and the result reaches much farther than the for-profit company you work for.
Oh anyone who does stuff like this is almost definitely on the clock. It may have started out with people tinkering with an OS as a hobby, but modern Linux, the fairly reliable multi-platform behemoth kernel we use today, relies on huge companies like Microsoft, IBM, VMWare, AWS, Google, etc. hiring the maintainers and paying them to maintain the kernel. It could never work if it was all evenings-and-weekends people. It’s just too much work.
And that’s fine! It’s incredible that a collaborative effort like Linux (protected by the GPL, which forces the issue) can pull in all these big companies’ resources, given that the companies would probably prefer to have their employees work on things that only benefit them and not their competitors.
I think the key difference is: being payed with a deadline or being payed with a purpose.
The first might produce quick, but unsustainable or less perfect results, the latter might take more time but will provide significant benefits (in this case for maintenance, time wasted/energy consumed by build pipelines on a global scale).
Ingo is employed by Red Hat, and his job is presumably to maintain the linux kernel. He may well love his job, but he is also technically on the clock.
