I'm not sure if there's an established protocol for this (even if it's not an official one), but thought those most experienced with open source might want to share with us.
I'm aware that random patches submitted to open source projects are never paid. They may be indirectly funded by a client but they're never paid for by the open source project itself.
But how about core developers? I heard for example that drupal has some 800 core developers behind it. Core developers means that they work on drupal core itself and together they push the main releases, so they're very important to the project. Of course drupal is just an example, but in general, is there any established protocol in the open source world that defines whether the company behind the project is expected to pay them and do these core developers expect such payment?
Any facts or first hand experiences?