Unity provides several tools to inspect the internal structure and contents of AssetBundles to help with troubleshooting.
WebExtract and Binary2Text are low-level command-line tools included with every Unity Editor installation.
WebExtract: Extracts the files embedded within an AssetBundle, similar to unzipping an archive. It creates a folder (named after the AssetBundle) containing its internal files in the same directory as the AssetBundle.Binary2Text: Converts a binary SerializedFile (the core Unity data format) into a human-readable text format, similar to Unity’s YAML format.You can find these tools in the following default install locations:
Windows:
C:\Program Files\Unity\Editor\Data\Tools
macOS
/Applications/Unity/Unity.app/Contents/Tools
You must first run WebExtract with the command WebExtract <FilePathToSceneBundle>, and then run binary2text.exe <path_to_extracted_SerializedFile> to creates a .txt file alongside the SerializedFile.
Adding -typeinfo to binary2text.exe provides a detailed listing of all type information within the SerializedFile. This includes Unity types, MonoBehaviour-based C# classes, and [SerializeReference] types, which is useful for debugging code stripping, missing types, or serialization mismatches between Unity versions.
Binary2Text requires the exact same version of Unity that was used to create the SerializedFile. The output can take up gigabytes of space for large AssetBundles, making it hard to manipulate.
UnityDataTools is a newer alternative to WebExtract and Binary2Text. It contains the following features:
dump Option: Opens an AssetBundle and produces text dumps of each SerializedFile it contains directly in the current working folder, without requiring a full binary extraction first. This behavior is similar to binary2text.analyze Option: Populates an SQLite database with detailed information about the AssetBundle’s contents. This is faster than binary2text and can handle large object and asset counts that UI tools might struggle with.For more information, refer to the UnityDataTools repository.
The BuildReport file (located at Library/LastBuild.buildreport in your project directory) is a Unity SerializedFile that records the content of each AssetBundle. This SerializedFile contains detailed information about the build, including timings for build steps and a granular view of AssetBundle contents. You can view this file in the following ways:
BuildReport contents within the Editor.BuildReports, but might struggle with large builds that involve many objects.BuildReport to access to the data within the BuildReport file.BuildReport directly as YAML text.