What is the super interface of WebDriver in Selenium?

SearchContext  ← Super interface
    └── WebDriver  ← Extends SearchContext
            ├── ChromeDriver
            ├── FirefoxDriver
            ├── EdgeDriver
            ├── RemoteWebDriver
            └── ...

public interface SearchContext {
    // Find a single element
    WebElement findElement(By by);

    // Find multiple elements
    List<WebElement> findElements(By by);
}

public interface WebDriver extends SearchContext {
    void get(String url);
    String getTitle();
    String getCurrentUrl();
    String getPageSource();
    void close();
    void quit();
    Set<String> getWindowHandles();
    String getWindowHandle();
    Options manage();
    Navigation navigate();
    TargetLocator switchTo();
    // ... plus findElement() and findElements() inherited from SearchContext
}

// Searching from the document root (WebDriver implements SearchContext)
driver.findElement(By.id("container"));

// Searching within a specific element (WebElement also implements SearchContext)
WebElement container = driver.findElement(By.id("container"));
WebElement button = container.findElement(By.tagName("button")); // Scoped search!

SearchContext
  ├── WebDriver (browser-level search)
  │     ├── ChromeDriver
  │     ├── FirefoxDriver
  │     └── RemoteWebDriver
  └── WebElement (element-level search)
        ├── RemoteWebElement
        └── ...