Added Rumble. Thanks to [H]ard|Forum for sponsoring this addition.
Updated lazy loader. It may help with dynamically-sized embeds (e.g. tweets) being cut off.
Updated Twitter. Tweets are now slightly wider (550px vs 500px) and should load imperceptibly faster.

A word about embedded tweets. At the time of writing, embedding a text-only tweet using Twitter's default method requires 20+ HTTP requests and 3.5 MB of resources. This update reduces both by approximately 10% and saves about 100 ms on loading time on a fast network. It is unclear why Twitter loads 3.4 MB of JavaScript to display ~140 characters of black-and-white text.
The new CSS should be functionally identical but please feel free to report any potential layout issues.
The style changes introduced in 2.6.11 have been reverted as a precautionary measure.
Added support for lazy loading in Chat 2 by Siropu. Thanks to for sponsoring this feature.

Updated CSS to fix a layout issue. Great care was taken in considering and avoiding any unwanted side effects but those can always occur so please feel free to report any potential layout issues.
Unsupported Amazon and BBC News URLs have been excluded.
Lazy loading has been enabled in conversations.
New CSS has been added for compatibility with XFMG 2.2

You don't have to upgrade if you don't use the XenForo Media Gallery add-on.
Getty Images now uses HTTPS to retrieve an image's dimensions.
Gfycat is now HD by default.
Added support for more Medium URLs.
Support for has been added.
All phrases used in the add-on's options and footer are now translatable.
Added support for Castos. Thanks to Ask Andy About Clothes for sponsoring this addition.
Stitcher has been updated to support their shortlink URLs.
Vimeo has been updated and remains functionally the same.

Starting with this update, the release version of add-on will be tested on XenForo 2.2.
The lazy loader has been updated to load visible elements more aggressively. In previous versions, the lazy loader would wait up to 3 seconds for the rest of the page to completely load before displaying embedded content. Starting with this update, visible (on-screen) elements are loaded immediately and will compete for resources with the rest of the page. This will prevent slow resources such as ads and large images from delaying embedded content.