Nitpicking one point:

> On non-Linux systems, additional software is required. Thus, TAR+GZIP is not established in our sense.

However, "established" means:

> 1. The file format has already been around for a long time.

> 2. The file format is supported by several vendors (and not just by a single company).

> 3. The file format is platform-independent, i.e., it enjoys support on Windows machines, Macs, and Unix-based systems.

Point #3 strikes me as odd since there's been tar support on Windows for a long time (and vendor support from Apple since OS X). To double-check, libarchive's release notes mention "Much improved Windows support, thanks largely to Michihiro NAKAJIMA. In particular, the test suites now build and run on Windows" back in 2009 at https://github.com/libarchive/libarchive/wiki/ReleaseNotes -- and that's only one of many ways to use tar on Windows.

So, perhaps the author means the OS vendor must supply a tar implementation to be "established"?

Thing is, "BSD-tar has been included in Microsoft Windows since Windows 10 April 2018 Update" says https://en.wikipedia.org/wiki/Tar_(computing)#History and https://docs.microsoft.com/en-us/virtualization/community/te... says "you'll also be able to extract files in formats in addition to .zip (like .tar.gz, for example)."

Okay, so perhaps the author wasn't quite up to date with Windows?

But elsewhere the author says this about FLAC:

> Apple products (iOS, Mac, Safari) do not natively support FLAC — quite possibly because Apple has its own lossless audio format, ALAC. However, players for FLAC can be easily found also for Apple systems. FLAC is thus an established file format.

I don't see how FLAC can be an established format when tar+gz is not.