All of the packages are significantly smaller -- not just those for macOS. So this isn't due to anything specific to the macOS package(s). Looking at the release notes for Go 1.21.0 I don't see an obvious explanation for the reduction. Downloading and extracting those two packages shows the contents have a proportional size difference:
> du -sh go1.20.7/ go1.21.0/
264M go1.20.7/
237M go1.21.0/
Most of the files and directories are larger in the 1.21.0 release. There are some notable exceptions. The main one, accounting for most of the decrease, is the tool directory: This is the `df -k` diff:
< 111520 ./pkg/tool/darwin_arm64
---
> 80704 ./pkg/tool/darwin_arm64
That is a 3 MB reduction (28%) in the total size of the Go tools. Why are the Go tools so much smaller? I don't see an obvious answer in the release notes.