Repository: yt-dlp
Issue: Dropbox Replay Support
Labels: site-request

### Checklist

- [X] I'm reporting a new site support request
- [X] I've verified that I'm running yt-dlp version **2022.07.18** ([update instructions](https://github.com/yt-dlp/yt-dlp#update)) or later (specify commit)
- [X] I've checked that all provided URLs are playable in a browser with the same IP and same login details
- [X] I've checked that none of provided URLs [violate any copyrights](https://github.com/ytdl-org/youtube-dl#can-you-add-support-for-this-anime-video-site-or-site-which-shows-current-movies-for-free) or contain any [DRM](https://en.wikipedia.org/wiki/Digital_rights_management) to the best of my knowledge
- [X] I've searched the [bugtracker](https://github.com/yt-dlp/yt-dlp/issues?q=) for similar issues **including closed ones**. DO NOT post duplicates
- [X] I've read the [guidelines for opening an issue](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#opening-an-issue)
- [X] I've read about [sharing account credentials](https://github.com/yt-dlp/yt-dlp/blob/master/CONTRIBUTING.md#are-you-willing-to-share-account-details-if-needed) and am willing to share it if required

### Region

USA

### Example URLs

- Single video: https://replay.dropbox.com/share/u8d4G0g3Cc0sSswy?video_version_id=pid_rvv%3AAAAAAJJPuon-ZWgXXEb3oQQ3fsJPgEeXr8rZySdnl1g9VAEA

### Provide a description that is worded well enough to be understood

Dropbox now provides a streaming like service. While some videos do require login / cookies / authentication, there are other videos like the one above that are publicly accessible if you have the link. I would like to be able to download these videos with `yt-dlp`.

### Provide verbose output that clearly demonstrates the problem

- [X] Run **your** yt-dlp command with **-vU** flag added (`yt-dlp -vU <your command line>`)
- [X] Copy the WHOLE output (starting with `[debug] Command-line config`) and insert it below

### Complete Verbose Output

```shell
❯ yt-dlp 'https://replay.dropbox.com/share/u8d4G0g3Cc0sSswy?video_version_id=pid_rvv%3AAAAAAJJPuon-ZWgXXEb3oQQ3fsJPgEeXr8rZySdnl1g9VAEA' -vU
[debug] Command-line config: ['https://replay.dropbox.com/share/u8d4G0g3Cc0sSswy?video_version_id=pid_rvv%3AAAAAAJJPuon-ZWgXXEb3oQQ3fsJPgEeXr8rZySdnl1g9VAEA', '-vU']
[debug] Encodings: locale UTF-8, fs utf-8, pref UTF-8, out utf-8, error utf-8, screen utf-8
[debug] yt-dlp version 2022.07.18 [135f05e]
[debug] Python 3.9.13 (CPython 64bit) - macOS-11.6-arm64-arm-64bit
[debug] Checking exe version: ffmpeg -bsfs
[debug] Checking exe version: avconv -bsfs
[debug] Checking exe version: ffprobe -bsfs
[debug] Checking exe version: avprobe -bsfs
[debug] exe versions: none
[debug] Optional libraries: Cryptodome-3.15.0, brotli-1.0.9, certifi-2022.06.15, mutagen-1.45.1, sqlite3-2.6.0, websockets-10.3
[debug] Proxy map: {}
[debug] Fetching release info: https://api.github.com/repos/yt-dlp/yt-dlp/releases/latest
Latest version: 2022.07.18, Current version: 2022.07.18
yt-dlp is up to date (2022.07.18)
[debug] [generic] Extracting URL: https://replay.dropbox.com/share/u8d4G0g3Cc0sSswy?video_version_id=pid_rvv%3AAAAAAJJPuon-ZWgXXEb3oQQ3fsJPgEeXr8rZySdnl1g9VAEA
[generic] u8d4G0g3Cc0sSswy?video_version_id=pid_rvv:AAAAAJJPuon-ZWgXXEb3oQQ3fsJPgEeXr8rZySdnl1g9VAEA: Downloading webpage
WARNING: [generic] Falling back on generic information extractor.
[generic] u8d4G0g3Cc0sSswy?video_version_id=pid_rvv:AAAAAJJPuon-ZWgXXEb3oQQ3fsJPgEeXr8rZySdnl1g9VAEA: Extracting information
[debug] Looking for video embeds
ERROR: Unsupported URL: https://replay.dropbox.com/share/u8d4G0g3Cc0sSswy?video_version_id=pid_rvv%3AAAAAAJJPuon-ZWgXXEb3oQQ3fsJPgEeXr8rZySdnl1g9VAEA
Traceback (most recent call last):
  File "/opt/homebrew/Cellar/yt-dlp/2022.7.18/libexec/lib/python3.9/site-packages/yt_dlp/YoutubeDL.py", line 1431, in wrapper
    return func(self, *args, **kwargs)
  File "/opt/homebrew/Cellar/yt-dlp/2022.7.18/libexec/lib/python3.9/site-packages/yt_dlp/YoutubeDL.py", line 1506, in __extract_info
    ie_result = ie.extract(url)
  File "/opt/homebrew/Cellar/yt-dlp/2022.7.18/libexec/lib/python3.9/site-packages/yt_dlp/extractor/common.py", line 644, in extract
    ie_result = self._real_extract(url)
  File "/opt/homebrew/Cellar/yt-dlp/2022.7.18/libexec/lib/python3.9/site-packages/yt_dlp/extractor/generic.py", line 4108, in _real_extract
    raise UnsupportedError(url)
yt_dlp.utils.UnsupportedError: Unsupported URL: https://replay.dropbox.com/share/u8d4G0g3Cc0sSswy?video_version_id=pid_rvv%3AAAAAAJJPuon-ZWgXXEb3oQQ3fsJPgEeXr8rZySdnl1g9VAEA
```
```