/usr/include/llvm-4.0/llvm/DebugInfo/MSF/ is in llvm-4.0-dev 1:4.0.1-10.
This file is owned by root:root, with mode 0o755.
..
/usr/include/llvm-4.0/llvm/DebugInfo/MSF/ByteStream.h
/usr/include/llvm-4.0/llvm/DebugInfo/MSF/IMSFFile.h
/usr/include/llvm-4.0/llvm/DebugInfo/MSF/MSFBuilder.h
/usr/include/llvm-4.0/llvm/DebugInfo/MSF/MSFCommon.h
/usr/include/llvm-4.0/llvm/DebugInfo/MSF/MSFError.h
/usr/include/llvm-4.0/llvm/DebugInfo/MSF/MSFStreamLayout.h
/usr/include/llvm-4.0/llvm/DebugInfo/MSF/MappedBlockStream.h
/usr/include/llvm-4.0/llvm/DebugInfo/MSF/SequencedItemStream.h
/usr/include/llvm-4.0/llvm/DebugInfo/MSF/StreamArray.h
/usr/include/llvm-4.0/llvm/DebugInfo/MSF/StreamInterface.h
/usr/include/llvm-4.0/llvm/DebugInfo/MSF/StreamReader.h
/usr/include/llvm-4.0/llvm/DebugInfo/MSF/StreamRef.h
/usr/include/llvm-4.0/llvm/DebugInfo/MSF/StreamWriter.h