Attention: this is the key used to sign the certificate requests, anyone holding this can sign certificates on your behalf. So keep it in a safe place!
openssl genrsa -des3 -out rootCA.key 4096
This process would likely apply to other Homebrew formula also.
First search for your desired package:
brew search go
You should get a list of results that include the below. Not "go" is very unspecific so you may get a lot of results: