Some templates store metadata in display:none-ed text; MediaViewer's whitelistHtml function makes this metadata visible. E.g. permission text shown for PD images starts with "Public domainPublic domainfalsefalse".
Version: unspecified
Severity: normal
URL: https://www.mediawiki.org/wiki/File:Annotated_screenshot_of_bug_in_Media_Viewer%27s_license_display.png