Installing a packed extension using DNR leads to this install warning on the extension object - "Cannot load extension with file or directory name _metadata. Filenames starting with "_" are reserved for use by the system.". However, possibly due to issue 879355, these are not shown to the user. 


Stack trace:

1   Chromium Framework                  0x000000011897b4da extensions::file_util::CheckForIllegalFilenames(base::FilePath const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >*) + 490
2   Chromium Framework                  0x000000011897ad3b extensions::file_util::ValidateExtension(extensions::Extension const*, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >*, std::__1::vector<extensions::InstallWarning, std::__1::allocator<extensions::InstallWarning> >*) + 347
3   Chromium Framework                  0x000000011897aaa0 extensions::file_util::LoadExtension(base::FilePath const&, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> > const&, extensions::Manifest::Location, int, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >*) + 160
4   Chromium Framework                  0x000000011897a9de extensions::file_util::LoadExtension(base::FilePath const&, extensions::Manifest::Location, int, std::__1::basic_string<char, std::__1::char_traits<char>, std::__1::allocator<char> >*) + 46
5   Chromium Framework                  0x0000000118ecc454 extensions::CrxInstaller::ReloadExtensionAfterInstall(base::FilePath const&) + 276