Analysis of information sources in references of the Wikipedia article "Project Builder" in English language version.
Xcode is based on Project Builder, an IDE you use to write programs for the NeXTSTEP operating system, the forerunner of Mac OS X
A free copy of Project Builder was bundled with every copy of OS X
...Included in the package was an IDE—Project Builder—that was a tweaked version of the IDE that came with NeXT, the OS whose acquisition laid much of the foundation for OS X. In 2003, Project Builder became the now familiar Xcode...
