Problem
Clicking video links on https://integration.wikimedia.org/ci/job/mwext-mw-selenium-jessie/725/
do not work :(
Reason
Jenkins Content Security Policy defaults to sandbox; default-src 'none'; img-src 'self'; style-src 'self';:
Specially default-src 'none' probihits loading scripts, URLs for AJAX/XHR/WebSockets/EventSources, fonts, plugin objects, media, and frames from anywhere.
Images and styles are allowed via img-src 'self' and style-src 'self'
Might want to set media-src: self.
Work-around
Download the video (right-click, save-as) and play it locally (it's not actually corrupt, even if your browser says it is).