This is correct. The format was really nice during the NeXTStep era. It was an simple ASCII plist file called PB.project. It could be edited by a human.

When Apple started "improving" stuff it turned into the SomeProject.pbproj/project.pbxproj file and was not editable by a human. This file would later become SomeProject.xcode/project.pbxproj and then SomeProject.xcodeproj/project.pbxproj all the while getting worse and worse and less editable and less readable/understandable.

Here is the entire project file (PB.project) for IORegistryExplorer from Mac OS X 10.0

    {
        APPCLASS = NSApplication; 
        DYNAMIC_CODE_GEN = YES; 
        English_RESOURCES = {}; 
        FILESTABLE = {
            CLASSES = (
                RExplorer.m, 
                "RExplorer-OutlineDelegate.m", 
                "RExplorer-BrowserDelegate.m", 
                CustomOutlineView.m, 
                RSearch.m, 
                RBool.m
            ); 
            English_INTERFACES = (IORegistryExplorer.nib); 
            FRAMEWORKS = (AppKit.framework, Foundation.framework, IOKit.framework, System.framework); 
            FRAMEWORKSEARCH = (); 
            H_FILES = (
                RExplorer.h, 
                CustomOutlineView.h, 
                "RExplorer-OutlineDelegate.h", 
                "RExplorer-BrowserDelegate.h", 
                RSearch.h, 
                RBool.h
            ); 
            IMAGES = (IORE.tiff); 
            INTERFACES = (); 
            OTHER_LINKED = (IORegistryExplorer_main.m); 
            OTHER_RESOURCES = (IORE.icns); 
            OTHER_SOURCES = (Makefile.preamble, Makefile, Makefile.postamble, CustomInfo.plist); 
            SUBPROJECTS = (); 
        }; 
        LANGUAGE = English; 
        MAKEFILEDIR = "$(MAKEFILEPATH)/pb_makefiles"; 
        NEXTSTEP_APPICON = IORE.tiff; 
        NEXTSTEP_BUILDTOOL = /bin/gnumake; 
        NEXTSTEP_DOCUMENTEXTENSIONS = (); 
        NEXTSTEP_INSTALLDIR = "$(SYSTEM_DEVELOPER_APPS_DIR)"; 
        NEXTSTEP_JAVA_COMPILER = /usr/bin/javac; 
        NEXTSTEP_MAINNIB = IORegistryExplorer.nib; 
        NEXTSTEP_OBJCPLUS_COMPILER = /usr/bin/cc; 
        PDO_UNIX_BUILDTOOL = $NEXT_ROOT/Developer/bin/make; 
        PDO_UNIX_INSTALLDIR = /Applications; 
        PDO_UNIX_JAVA_COMPILER = "$(JDKBINDIR)/javac"; 
        PDO_UNIX_OBJCPLUS_COMPILER = "$(NEXTDEV_BIN)/gcc"; 
        PROJECTNAME = IORegistryExplorer; 
        PROJECTTYPE = Application; 
        PROJECTVERSION = 2.8; 
        WINDOWS_BUILDTOOL = $NEXT_ROOT/Developer/Executables/make; 
        WINDOWS_INSTALLDIR = /Applications; 
        WINDOWS_JAVA_COMPILER = "$(JDKBINDIR)/javac.exe"; 
        WINDOWS_MAINNIB = "IORegistryExplorer-windows.nib"; 
        WINDOWS_OBJCPLUS_COMPILER = "$(DEVDIR)/gcc"; 
    }

Simple. Elegant. Usable.