I recently got a Mac, my motivation--coming from Linux--was to find out why Linux projects from developers working on Macs I came across ended up being the maintenance burden for me and my team that they were. Surprising insights.
I have a Unify Dream Machine Pro, so I at least have some insight how much traffic it generated even if an installer for some reason does not want to tell you. I acknowledge that it may be sufficient for Mac users at home to just tell them how long it will take, while game launchers show all kinds of statistics about downloads, but for developers... oh come on Apple!
You won't trust me if I'm not going to post a screenshot, so here it is:

The SSL/TLS connection which downloaded 189 MB was the Visual Studio Code download which instructed me to install the developer tools. So for version 2395 we have 2.84 GB of data.
When I log into the developer portal I can see downloads which are not more than 700 MB in size like Command Line Tools for Xcode 13.4. The numbers don't add up here.
bt@Benjamins-MacBook-Pro ~ % git --version
xcode-select: note: no developer tools were found at '/Applications/Xcode.app', requesting install. Choose an option in the dialog to download the command line developer tools.
bt@Benjamins-MacBook-Pro ~ % git --version
git version 2.30.1 (Apple Git-130)
bt@Benjamins-MacBook-Pro ~ % xcode-select --print-path
/Library/Developer/CommandLineTools
bt@Benjamins-MacBook-Pro ~ % xcode-select --version
xcode-select version 2395.
bt@Benjamins-MacBook-Pro ~ % du -hs /Library/Developer/CommandLineTools/
2.1G /Library/Developer/CommandLineTools/
The device is an M1 powered MBP late 2021 with macOS 12.4.
Looking further, now "Software Update" from the control panel tells me that there are updates available for Command Line Tools for Xcode 13.2, 13.3 and 13.4. Each around 590 to 740 MB. So you download old software to then download newer software and 3 different releases. This will make sense at some point in my Mac journey, but for the start I only wanted git-cli which should be no more than 50 MB, at least that would be close to what Ubuntu does including direct dependencies.
When I have time I will try to set up a proxy to identify what it downloads, but that has to wait. Trying to use my sonatype nexus repository from the command line as a raw proxy did not work, I guess because it starts a GUI and ignores http_proxy, https_proxy, HTTP_PROXY and HTTPS_PROXY variables.
git
, likejava
, are stub binaries. Apple doesn’t shipgit
proper with the OS. The stub invokes an installer that will download via a network call a signed copy of the entire framework. Installer is suitable for your CPU type and patched as of when you install it as opposed to when Apple cut the GM seed of macOS. This is how Apple rolls now - same as with legal requirements in Russia where apps install you.