We are very excited to create a standalone repo for this old/ancient tool in Nissl Lab. This tool exists for a long time although not many developers know it. It was located in NPOI repo/tools/POIFS Browser folder.

POIFS Explorer

This is a tool originally created by Huseyin Tufekcilerli in 2009. The previous name is POIFS Browser.

What is POIFS Explorer

This is a tool to inspect any OLE2 Document compatible files (or ActiveX documents).

Supported files

• .xls Excel document
• .doc Word document
• .ppt Powerpoint document
• .poifs
• .cpk PAL3 仙剑奇侠传（三） assets file (Thanks to Jiaqi Liu for his CPK.NET library)

Interesting Old Story of this Tool

At the begining, I thought only NPOI team use this tool to view the generated/existing OLE2 files. However, someone from PHP Excel team reaching me via email and say hey, we also use this tool. Then I found there are more users than we originally thought.

Open source is always about sharing love and spirit. It's not just .NET community. Sometimes, it's usually cross language community. We always have some new discoveries from other language community to see that aha, they have the tool. Why do we re-create the wheel if it's usable and there is no extra feature if we do code migration? Just Use IT instead of Just Do IT :D