We should show all time information localized to the browser's settings. For example, the current HTML for revision history shows time in localized language, UTC timezone:
<a href="..." title="..." class="mw-changeslist-date">23:52, 18 February 2015</a>
Instead, we could show this HTML which can be dynamically changed to localized version with a simple JavaScript. In case JS is not available, the text would simply remain in UTC.
<a href="..." title="..." class="mw-changeslist-date"><time datetime="2015-02-18 23:52">23:52, 18 February 2015 UTC</time></a>