How to merge and extract tgz files from Google Takeout?

Source: https://gist.github.com/chabala/22ed01d7acf9ee0de9e3d867133f83fb

One solution that works for me on Mac:

pv takeout-* | gtar -xzif -

Where we need to install pv and gnu-tar from Homebrew, i.e.,

brew install pv
brew install gnu-tar