VersionControlManager.versionControlDescriptors

Description

An array containing all available version control systems.

Each VersionControlDescriptor contains a unique VCS name. You can pass the VCS name to SetVersionControl to activate that VCS.

using UnityEditor;
using UnityEditor.VersionControl;
using UnityEngine;

static class Example
{
    [MenuItem("Example/Print Available VCS")]
    static void PrintAvailableVCS()
    {
        var message = "Available version control systems:";
        foreach (var descriptor in VersionControlManager.versionControlDescriptors)
            message += " " + descriptor.displayName;
        Debug.Log(message);
    }
}

Additional resources: VersionControlManager, VersionControlObject, VersionControlDescriptor.