New archivers support: Brotli, LZ4 and ZStd about puremagic HOT 3 CLOSED

well, on linux you can easily install the programs and create the test files yourself:

$ sudo apt install brotli lz4 zstd
$ touch test.txt
$ brotli -k test.txt
$ lz4 -k test.txt
$ zstd -k test.txt

I uploaded results:

• http://stokito.com/test.txt.br
• http://stokito.com/test.txt.lz4
• http://stokito.com/test.txt.zst
  Please download them until my site is working.

Magics:

• Brotli: doesn't have a magic number. We can only determine it by the file extension .br.
• LZ4: 4 Bytes, Little endian format. Value : 0x184D2204 https://github.com/lz4/lz4/blob/master/doc/lz4_Frame_format.md
• ZStandard: Little endian 0xFD2FB528

Mime types:

• application/x-brotli and application/x-brotli-compressed-tar for tar.br files
• application/x-lz4 and application/x-lz4-compressed-tar for tar.lz4 or tlz4 files
• application/zstd (without the -x) and application/x-zstd-compressed-tar for tar.zst or tzst files

from puremagic.

Added brotil magic number in 1.7 for format 3 from google/brotli#298
lz4 and zst added in 1.6

from puremagic.

Thanks for bringing up these new formats, if you happen to have any of them please post example files.

from puremagic.