### Preflight Checklist

- [X] I have read the [Contributing Guidelines](https://github.com/electron/electron/blob/main/CONTRIBUTING.md) for this project.
- [X] I agree to follow the [Code of Conduct](https://github.com/electron/electron/blob/main/CODE_OF_CONDUCT.md) that this project adheres to.
- [X] I have searched the [issue tracker](https://www.github.com/electron/electron/issues) for a bug report that matches the one I want to file, without success.

### Electron Version

17.0.0

### What operating system are you using?

Windows

### Operating System Version

Windows 10 Version 21H1

### What arch are you using?

x64

### Last Known Working Electron version

14.2.3

### Expected Behavior

background should transparent if background is #00000000

### Actual Behavior

has a white background

### Testcase Gist URL

_No response_

### Additional Information

_No response_
shell/browser/api/electron_api_web_contents.cc
const std::string& content) {
  auto it = saved_files_.find(url);
  if (it == saved_files_.end())
    return;
   Notify DevTools.
  base::Value url_value(url);
  inspectable_ontents_->CallClientFunction("DevToolsAPI.appendedToURL",
                                                &url_value, nullptr, nullptr);
  file_task_runner_->PostTask(
      FROM_HERE, base::BindOnce(&AppendToFile, it->second, content));
}
void WebContents::DevToolsRequestFileSystems() {