While pest's focus is on accessibility, developers can sometimes struggle to understand what is going under the hood and why a particular input is parsed in a particular way (or fails to parse). A long time ago, @dragostis implemented a simple CLI debugger that could help in this aspect, but this effort was not finished. This implementation was revived and you are now welcome to use it. You should be able to install it using:
cargo install pest_debugger
See more details on: v2.5.0: introducing `pest_debugger` · Discussion #739 · pest-parser/pest · GitHub