Repository: yt-dlp
Issue: [Broken] BBC: Program page gives 404 error
Labels: site-bug

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## Checklist

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Carefully read and work through this check list in order to prevent the most common mistakes and misuse of yt-dlp:
- First of, make sure you are using the latest version of yt-dlp. Run `yt-dlp --version` and ensure your version is 2021.10.10. If it's not, see https://github.com/yt-dlp/yt-dlp#update on how to update. Issues with outdated version will be REJECTED.
- Make sure that all provided video/audio/playlist URLs (if any) are alive and playable in a browser.
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- [X] I'm reporting a broken site support
- [X] I've verified that I'm running yt-dlp version **2021.10.10**
- [X] I've checked that all provided URLs are alive and playable in a browser
- [X] I've checked that all URLs and arguments with special characters are properly quoted or escaped
- [X] I've searched the bugtracker for similar issues including closed ones
- [X] I've read the opening an issue section in CONTRIBUTING.md
- [X] I have given an appropriate title to the issue


## Verbose log

<!--
Provide the complete verbose output of yt-dlp that clearly demonstrates the problem.
Add the `-v` flag to your command line you run yt-dlp with (`yt-dlp -v <your command line>`), copy the WHOLE output and insert it below. It should look similar to this:
 [debug] System config: []
 [debug] User config: []
 [debug] Command-line args: [u'-v', u'http://www.youtube.com/watch?v=BaW_jenozKc']
 [debug] Encodings: locale cp1251, fs mbcs, out cp866, pref cp1251
 [debug] yt-dlp version 2021.10.10
 [debug] Python version 2.7.11 - Windows-2003Server-5.2.3790-SP2
 [debug] exe versions: ffmpeg N-75573-g1d0487f, ffprobe N-75573-g1d0487f, rtmpdump 2.4
 [debug] Proxy map: {}
 <more lines>
-->

```
[debug] Command-line config: ['-Uv', 'https://www.bbc.co.uk/programmes/m000tsg9']
[debug] Encodings: locale UTF-8, fs utf-8, out utf-8, pref UTF-8
[debug] yt-dlp version 2021.10.10
[debug] Python version 3.9.7 (CPython 64bit) - Linux-5.14.12-arch1-1-x86_64-with-glibc2.33
[debug] exe versions: ffmpeg 4.4, ffprobe 4.4
[debug] Optional libraries: Crypto, keyring, mutagen, sqlite, websockets
[debug] ANSI escape support: stdout = True, stderr = True
[debug] Proxy map: {}
yt-dlp is up to date (2021.10.10)
[debug] [bbc.co.uk] Extracting URL: https://www.bbc.co.uk/programmes/m000tsg9
[bbc.co.uk] m000tsg9: Downloading video page
[bbc.co.uk] m000tsg9: Downloading playlist JSON
[bbc.co.uk] m000tsg9: Downloading legacy playlist XML
ERROR: [bbc.co.uk] m000tsg9: Unable to download XML: HTTP Error 404: Not Found (caused by <HTTPError 404: 'Not Found'>); please report this issue on  https://github.com/yt-dlp/yt-dlp . Make sure you are using the latest version; see  https://github.com/yt-dlp/yt-dlp  on how to update. Be sure to call yt-dlp with the --verbose flag and include its complete output.
  File "/usr/lib/python3.9/site-packages/yt_dlp/extractor/common.py", line 698, in _request_webpage
    return self._downloader.urlopen(url_or_request)
  File "/usr/lib/python3.9/site-packages/yt_dlp/YoutubeDL.py", line 3228, in urlopen
    return self._opener.open(req, timeout=self._socket_timeout)
  File "/usr/lib/python3.9/urllib/request.py", line 523, in open
    response = meth(req, response)
  File "/usr/lib/python3.9/urllib/request.py", line 632, in http_response
    response = self.parent.error(
  File "/usr/lib/python3.9/urllib/request.py", line 561, in error
    return self._call_chain(*args)
  File "/usr/lib/python3.9/urllib/request.py", line 494, in _call_chain
    result = func(*args)
  File "/usr/lib/python3.9/urllib/request.py", line 641, in http_error_default
    raise HTTPError(req.full_url, code, msg, hdrs, fp)

```
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## Description

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When trying to download from a program page on the BBC website, yt-dlp shows a 404 error. Previously, these pages were treated as playlists, and all available episodes of the program were downloaded.