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Added
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* Author view to display custom message with instructions if no video url is detected. Also disable validations for author view to supress default validation failure messages.
Removed
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* `autoplay` from allow attribute passed to the iframe.
Changed
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* Title of `display_name` field to `Video Title` and modified the description.
* Default display name of the XBlock as displayed in the Advanced XBlocks selection list from `Video` to `Video Iframe`.