Oh, found it thanks to Chromium's awesome codesearch. Turns out it's no JS! https://code.google.com/p/chromium/issues/detail?id=136534 … Chromium only though, not a standard :(
You can add location information to your Tweets, such as your city or precise location, from the web and via third-party applications. You always have the option to delete your Tweet location history. Learn more
Oh, found it thanks to Chromium's awesome codesearch. Turns out it's no JS! https://code.google.com/p/chromium/issues/detail?id=136534 … Chromium only though, not a standard :(