Package manager for macOS (or Linux), see more at https://brew.sh

A third-party (in relation to Homebrew) repository providing installable packages (formulae) on macOS and Linux.

See more at https://docs.brew.sh/Taps

brew install certonid/tap/certonid

You can also add the tap which makes formulae within it available in search results (brew search output):

brew tap certonid/tap
brew install certonid

brew help, man brew or check Homebrew's documentation.