/usr/include/thunderbird/google/protobuf/ is in thunderbird-dev 1:52.8.0-1~deb8u1.
This file is owned by root:root, with mode 0o755.
..
/usr/include/thunderbird/google/protobuf/descriptor.h
/usr/include/thunderbird/google/protobuf/descriptor.pb.h
/usr/include/thunderbird/google/protobuf/descriptor_database.h
/usr/include/thunderbird/google/protobuf/dynamic_message.h
/usr/include/thunderbird/google/protobuf/extension_set.h
/usr/include/thunderbird/google/protobuf/generated_enum_reflection.h
/usr/include/thunderbird/google/protobuf/generated_message_reflection.h
/usr/include/thunderbird/google/protobuf/generated_message_util.h
/usr/include/thunderbird/google/protobuf/io/
/usr/include/thunderbird/google/protobuf/io/coded_stream.h
/usr/include/thunderbird/google/protobuf/io/coded_stream_inl.h
/usr/include/thunderbird/google/protobuf/io/gzip_stream.h
/usr/include/thunderbird/google/protobuf/io/package_info.h
/usr/include/thunderbird/google/protobuf/io/printer.h
/usr/include/thunderbird/google/protobuf/io/strtod.h
/usr/include/thunderbird/google/protobuf/io/tokenizer.h
/usr/include/thunderbird/google/protobuf/io/zero_copy_stream.h
/usr/include/thunderbird/google/protobuf/io/zero_copy_stream_impl.h
/usr/include/thunderbird/google/protobuf/io/zero_copy_stream_impl_lite.h
/usr/include/thunderbird/google/protobuf/message.h
/usr/include/thunderbird/google/protobuf/message_lite.h
/usr/include/thunderbird/google/protobuf/package_info.h
/usr/include/thunderbird/google/protobuf/reflection_ops.h
/usr/include/thunderbird/google/protobuf/repeated_field.h
/usr/include/thunderbird/google/protobuf/service.h
/usr/include/thunderbird/google/protobuf/stubs/
/usr/include/thunderbird/google/protobuf/stubs/atomicops.h
/usr/include/thunderbird/google/protobuf/stubs/atomicops_internals_arm64_gcc.h
/usr/include/thunderbird/google/protobuf/stubs/atomicops_internals_arm_gcc.h
/usr/include/thunderbird/google/protobuf/stubs/atomicops_internals_arm_qnx.h
/usr/include/thunderbird/google/protobuf/stubs/atomicops_internals_atomicword_compat.h
/usr/include/thunderbird/google/protobuf/stubs/atomicops_internals_generic_gcc.h
/usr/include/thunderbird/google/protobuf/stubs/atomicops_internals_macosx.h
/usr/include/thunderbird/google/protobuf/stubs/atomicops_internals_mips_gcc.h
/usr/include/thunderbird/google/protobuf/stubs/atomicops_internals_pnacl.h
/usr/include/thunderbird/google/protobuf/stubs/atomicops_internals_solaris.h
/usr/include/thunderbird/google/protobuf/stubs/atomicops_internals_tsan.h
/usr/include/thunderbird/google/protobuf/stubs/atomicops_internals_x86_gcc.h
/usr/include/thunderbird/google/protobuf/stubs/atomicops_internals_x86_msvc.h
/usr/include/thunderbird/google/protobuf/stubs/common.h
/usr/include/thunderbird/google/protobuf/stubs/hash.h
/usr/include/thunderbird/google/protobuf/stubs/map_util.h
/usr/include/thunderbird/google/protobuf/stubs/once.h
/usr/include/thunderbird/google/protobuf/stubs/platform_macros.h
/usr/include/thunderbird/google/protobuf/stubs/shared_ptr.h
/usr/include/thunderbird/google/protobuf/stubs/stl_util.h
/usr/include/thunderbird/google/protobuf/stubs/stringprintf.h
/usr/include/thunderbird/google/protobuf/stubs/strutil.h
/usr/include/thunderbird/google/protobuf/stubs/substitute.h
/usr/include/thunderbird/google/protobuf/stubs/template_util.h
/usr/include/thunderbird/google/protobuf/stubs/type_traits.h
/usr/include/thunderbird/google/protobuf/text_format.h
/usr/include/thunderbird/google/protobuf/unknown_field_set.h
/usr/include/thunderbird/google/protobuf/wire_format.h
/usr/include/thunderbird/google/protobuf/wire_format_lite.h
/usr/include/thunderbird/google/protobuf/wire_format_lite_inl.h