parj/xslb_reader ? reverse-engineered prompt

Build me a small Python package that can read Excel files, including xlsb, xlsx, and xlsm, without needing any third party dependencies. I want a simple API that can open a workbook, list the sheet names, read formulas and values, and also pull out pivot table info, sheet filters, and VBA module source when it exists.

Please also add a command line tool so I can point it at a file and get the contents back as dict, JSON, or markdown, and optionally limit it to one sheet or only certain kinds of data. If it makes sense, add an optional faster backend for large files, but keep the default version pure Python and easy to install.

If anything is unclear, look up current file format details online and keep iterating until it works on the sample files in the repo.