I just wanted a simple tool to do the following:

• Browse the tree of a .unitypackage file
• Extract some individual files
• All without having to start Unity

So I threw this together for my own use. Maybe it could be helpful to others.

This is a Java program requiring Java 8 or higher.

• Run with Java
• Accepts a .unitypackage as a program argument to open immediately
• Open .unitypackage files using the Open button, or drag and drop a .unitypackage onto the window
• Search by name or GUID in the text box and press Enter or the Search button
• Expand/Collapse the tree
• Files with a preview will appear in the preview box
• Extract the selected item into the same directory as the .unitypackage. The directory will be opened in your OS file viewer.
• Right-click to copy name, size, or GUID
• History.ini saves the last directory used

Alternatively, it can extract everything from the command line using the --extract-all command

java -jar UnityPackageViewer.x.x.x.jar path/to/file.unitypackage --extract-all

• This is beta quality software. No rigorous testing has been done. It probably has bugs. Only tested with data as I make use of it.

• All I know about the .unitypackage file format came from examining several files, and reading code from some existing tools. I didn't read any specification (assuming there is one). There could certainly be edge cases this misses.

A .unitypackage is just a compressed TAR archive. Inside it contains several root directories (in most cases). Each directory name is a GUID (in most cases).

Inside each of them is the contents of the asset with that GUID. Specifically, each GUID directory contains some of these 4 files (among others).

• pathname First line of text is the full path of the asset where it will appear when imported into Unity.
• asset.meta The corresponding .meta file.
• asset Contains the actual asset payload. Won't exist for directories.
• preview.png Optional preview of some types of assets.

It's not difficult to build up the structure of what's shown when you import into unity.

As shown in Unity:

As shown in this tool:

https://gist.github.com/yasirkula/dfc43134fbfefb820d0adbc5d7c25fb3 A very nice Unity script to explore .unitypackages

https://github.com/Switch-9867/UnitypackgeExtractor C# command-line tool

https://github.com/ntrf/UnityUnpack Haxe command-line tool

https://github.com/Cobertos/unitypackage_extractor Python command-line tool. Its associated pypi package at https://pypi.org/project/unitypackage-extractor/

https://github.com/FatihBAKIR/UnityPacker C# "Create unitypackages without unity, from command line"

https://github.com/ngyewch/UnityPackager Java library and command line tools to manipulate .unitypackage files.