For videos with subtitles the original HTML (i.e. before manipulation by the JS player) contains track elements like
```
<track kind="subtitles"
data-mwtitle="TimedText:Edward_Snowden_speaks_about_NSA_programmes_at_Sam_Adams_award_presentation_in_Moscow.webm.en.srt"
data-mwprovider="wikimediacommons"
type="text/x-srt"
src="https://commons.wikimedia.org/w/index.php?title=:Edward+Snowden+speaks+about+NSA+programmes+at+Sam+Adams+award+presentation+in+Moscow.webm.en.srt&action=raw&ctype=text%2Fx-srt"
srclang="en"
data-dir="ltr"
label="English (en) Untertitel">
```
(You can get this by putting `[[File:Edward Snowden speaks about NSA programmes at Sam Adams award presentation in Moscow.webm]]` on a page and previewing it.)
The URL https://commons.wikimedia.org/w/index.php?title=:Edward+Snowden+speaks+about+NSA+programmes+at+Sam+Adams+award+presentation+in+Moscow.webm.en.srt&action=raw&ctype=text%2Fx-srt returns a 404 error, note the missing namespace. It should be https://commons.wikimedia.org/w/index.php?title=TimedText:Edward+Snowden+speaks+about+NSA+programmes+at+Sam+Adams+award+presentation+in+Moscow.webm.en.srt&action=raw&ctype=text%2Fx-srt but even this isn't fully correct, as it uses text/x-wiki as mimetype, the `ctype` parameter is ignored.
The JS video player retrieves the subtitles using a different API request, so for users with JS enabled this bug is only noticeable in the browser console, but users with disabled JS will not see the subtitles, even if their browser supports the track element.