Code can still be published and merge requests can still be handled even if the code isn't under an open source license. As a prime example check out Unreal Engine. One of the most popular game engines that powers many AAA games and cinema today. They are not open source, but they actively take outside contributions on GitHub. Though unlike what the parent comment is saying Epic can afford to pay people to work on the project instead of having all of the work done for free.
alt Hacker News
Code can still be published and merge requests can still be handled even if the code isn't under an open source license. As a prime example check out Unreal Engine. One of the most popular game engines that powers many AAA games and cinema today. They are not open source, but they actively take outside contributions on GitHub. Though unlike what the parent comment is saying Epic can afford to pay people to work on the project instead of having all of the work done for free.