PBXUSER, Xcode Project User Data File (.pbxuser)
The PBXUSER Developer file format
PBXUSER files are most commonly associated with Xcode. Xcode is a software development program for users of Apple desktop computers running on Mac OS X. It allows developers to create software and applications for both Mac OS X and iOS. The file is used to store the user settings of a development project started or developed in Xcode. The user settings include all files that are currently opened, the window settings, build preferences, directories and other properties that are needed to set the user settings. The PBXUSER file is used to remember the local settings of Xcode and duplicate or re-use them for several projects.
Technical details of PBXUSER files
The user data stored in a PBXUSER file contain local user data only. That’s why they are not suited to be shared among developers or with the source code control in a collaborative project. The only exception is a file usually called “default.pbxuser”. This file is often used to give developers working on the same project the same starting template or base. PBXUSER files are usually found inside Xcode project files with the XCODEPROJ extension.