/usr/include/ is in gworkspace.app 0.9.3-1+b2.
This file is owned by root:root, with mode 0o755.
..
/usr/include/GNUstep/
/usr/include/GNUstep/DBKit/
/usr/include/GNUstep/DBKit/DBKBTree.h
/usr/include/GNUstep/DBKit/DBKBTreeNode.h
/usr/include/GNUstep/DBKit/DBKFixLenRecordsFile.h
/usr/include/GNUstep/DBKit/DBKPathsTree.h
/usr/include/GNUstep/DBKit/DBKVarLenRecordsFile.h
/usr/include/GNUstep/Frameworks/
/usr/include/GNUstep/Frameworks/FSNode.framework/
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/FSNBrowser.h
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/FSNBrowserCell.h
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/FSNBrowserColumn.h
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/FSNBrowserMatrix.h
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/FSNBrowserScroll.h
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/FSNFunctions.h
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/FSNIcon.h
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/FSNIconsView.h
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/FSNListView.h
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/FSNPathComponentsViewer.h
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/FSNTextCell.h
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/FSNode.h
/usr/include/GNUstep/Frameworks/FSNode.framework/Versions/0/FSNodeRep.h
/usr/include/GNUstep/Frameworks/Inspector.framework/
/usr/include/GNUstep/Frameworks/Inspector.framework/Versions/
/usr/include/GNUstep/Frameworks/Inspector.framework/Versions/0/
/usr/include/GNUstep/Frameworks/Inspector.framework/Versions/0/ContentViewersProtocol.h
/usr/include/GNUstep/Frameworks/Inspector.framework/Versions/0/Inspector.h
/usr/include/GNUstep/Frameworks/MDKit.framework/
/usr/include/GNUstep/Frameworks/MDKit.framework/Versions/
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/usr/include/GNUstep/Frameworks/MDKit.framework/Versions/0/MDKAttributeChooser.h
/usr/include/GNUstep/Frameworks/MDKit.framework/Versions/0/MDKAttributeEditor.h
/usr/include/GNUstep/Frameworks/MDKit.framework/Versions/0/MDKAttributeView.h
/usr/include/GNUstep/Frameworks/MDKit.framework/Versions/0/MDKQuery.h
/usr/include/GNUstep/Frameworks/MDKit.framework/Versions/0/MDKQueryManager.h
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/usr/include/GNUstep/Frameworks/MDKit.framework/Versions/0/MDKit.h
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/usr/include/GNUstep/FSNode
/usr/include/GNUstep/Inspector
/usr/include/GNUstep/MDKit
/usr/include/GNUstep/Operation