The com.unity.sentis package visibility issue in the Unity Editor typically stems from registry metadata delays or local cache conflicts during the transition between specific Unity 6 development cycles. While some builds might fail to list the package automatically, Sentis remains the primary framework for neural network inference and can be forcibly loaded. To resolve this, your project configuration must be updated manually:

1. Close the Unity Editor.
2. Navigate to your project root directory and open the Packages folder.
3. Open the manifest.json file using a standard text editor.
4. Locate the dependencies object and insert "com.unity.sentis": "2.1.1" (or the specific version required for your workflow).
5. Save the file and restart the Unity Editor to trigger a package re-resolve and download.

Additional Tips

• Use the Add package by name option in the Package Manager (+) menu as an alternative to manual file editing to verify connectivity.
• If the package still fails to appear, delete the PackageCache folder and the Library folder in your project directory to force a clean metadata fetch.
• Verify that the Unity Registry is selected in the Package Manager dropdown rather than In Project or My Assets.