Exercise 1: Why the .xib Format Was Added — Possible Solution
=============================================================

TASK
Explain why the .xib format was added to Interface Builder, and say what
that tells you about how interface files were being used in teams.

ANSWER
Interface Builder originally saved interfaces as .nib files, short for NeXT
Interface Builder. The .xib format, which is XML-based, was added as
version 3 because it is more suitable for storage in revision control
systems.

WHAT THAT SUGGESTS
Interface files were being kept in shared version control by teams, and a
format that works well there (plain text that can be compared and merged)
was worth adding. This is my reading of the source, which states only the
reason for the format and not the details of how teams used it.

CHECK
The reason for the change comes from the chapter's history of Interface
Builder. The inference about team practice is labeled as inference.