If you actually look at Apple's history with these, it's embarrassing for Apple.
Apple effectively abandoned CUPS when Michael R. Sweet left the company, which is why the OpenPrinting fork exists. For something like a year they let the project languish and accepted virtually no patches, either. No one but Apple uses Apple CUPS anymore.
Darwin is subject to periodic, incomplete code dumps to the point that for decades even getting it to build has been a struggle that includes tons of downstream work. At the moment, such efforts are in a historic slump; no recent stack is usable for anyone and it's been that way for years.
WebKit was a hostile fork (without any history of antagonism to motivate it) of KHTML, essentially classic code-over-the-wall stuff. Its original announcement was cause for consternation in the F/OSS community, not celebration.
LLVM I don't know much about the governance and maintenance of. Maybe someone else can speak to that.
But as useful as LLVM and WebKit have been to downstream projects, Apple's record with open-source is mixed at best.
Apple effectively abandoned CUPS when Michael R. Sweet left the company, which is why the OpenPrinting fork exists. For something like a year they let the project languish and accepted virtually no patches, either. No one but Apple uses Apple CUPS anymore.
Darwin is subject to periodic, incomplete code dumps to the point that for decades even getting it to build has been a struggle that includes tons of downstream work. At the moment, such efforts are in a historic slump; no recent stack is usable for anyone and it's been that way for years.
WebKit was a hostile fork (without any history of antagonism to motivate it) of KHTML, essentially classic code-over-the-wall stuff. Its original announcement was cause for consternation in the F/OSS community, not celebration.
LLVM I don't know much about the governance and maintenance of. Maybe someone else can speak to that.
But as useful as LLVM and WebKit have been to downstream projects, Apple's record with open-source is mixed at best.