Indeed, the old license [1] was not pure GPLv2, but a variant of GPLv2 with additional exceptions for Apple operating systems, allowing others to develop proprietary printer drivers for Apple operating systems. It even covered the use of the example code for this purpose without the need to release the source code of the resulting driver based on that.

[1] https://github.com/apple/cups/blob/branch-2.2/LICENSE.txt