Thank you, sneha rani
This looks like an interesting web app. However, if the video has closed captions on Twitter, the app will only download the video file, not the closed captions text file. And it will not apparently burn the closed captions onto the video.
Thank you for your helpful comments
There are a few ways to download a video with subtitles. One way is to use a video downloader tool that allows you to select the subtitles you want to include in the download. Another way is to use a video player that supports subtitles and allows you to download the video with the subtitles embedded in it. Additionally, you can also use a subtitle downloader tool to download the subtitle file separately and then add it to the video file using a video editing software.
A heartfelt "thank you" for taking me into account.
Thank you, Bianca: both for the detailed accuracy of your explanation, and for not having linked to resources in it
In fact, it is always safer to do as you did: explain how people can find what they need, and let them decide themselves which they can safely use.