This is an Unity package for the FaunaDB C# Driver. No custom changes, just a nice package to make it easier to integrate FaunaDB into an Unity project.
Open the Package Managed in the Unity Editor (Window/Package Manager). Then, click in the plus button to add a new package by selecting the Add package from git URL... option.
Type in this repository URL, you can use SSH git@github.com:cicanci/fauna-unity.git or HTTPS https://github.com/cicanci/fauna-unity.git.
Finally, the package will be imported and the Package Manager window will show you the version and other details. If you want to uninstall the package, just click in the Remove button in this screen after selecting the package in the left menu.
Official FaunaDB C# Driver repository: https://github.com/fauna/faunadb-csharp
Official FaunaDB C# documentation: https://docs.fauna.com/fauna/current/drivers/csharp