It is also an ancient Greek hat. This package is merely a bundle of scripts that we use at least occasionally to after performing a database search with Comet or Sage on DDA proteomics data. These are written with our data in mind, so your mileage may vary.
Petasus requires Python >= 3.10 and is pip installable:
pip install git+https://github.com/TalusBio/petasusPetasus is a command line tool. Each subcommand performs a different random of task that we've tried to describe adequately for its use.