The opensource.apple.com site is really more for software that they snapshot and release (open source, not open process). They've had other projects for a long

The opensource.apple.com site is really more for software that they snapshot and release (open source, not open process). They've had other projects for a long time developed in the open, and used to run https://www.macosforge.org https://www.macosforge.org to host them. Some of those were acquired (either as a core developer in the case of CUPS, a codebase in the case of WebKit) but I'm not sure of other examples of open sourcing an acquired technology like this.