Why does .tar.gz automatically extract the GZip archive when I download it in Safari? I downloaded a .tar.gz archive backup of a website.  Every time I download it, when I click the magnifying glass in Safari Downloads, it takes me to the file, but it's now just a .tar, and so is double the size.  

Nothing pops-up to say it's extracting.  

Is it just Safari doing it?  

I have "The Unarchiver", "Archive Utility", and "7GX" all installed ("Archive Utility" is the default).  Or is it just the way macOS displays it, and it is still GZipped?  

If I Zip it then it goes back to the size of the GZip.  Safari also only says it downloads a file the size of the .tar.gz, not the .tar.  Any ideas?

macOS Sierra 10.12.1 (16B2555) and Safari Version 10.0.1 (12602.2.14.0.7).
Disable 'Open "safe" files after downloading'.
Safari > Prefs > general