This tag marks a variable as not requiring escaping by the template engine,
potentially creating cross-site scripting vulnerabilities, so shouldn't be used
unless absolutely necessary. In these cases, I don't think it's necessary.
For now, this gives us more assurance that other sites will choose the
preview we want.
You can control the selection by adding data-ogpreview to image, video, and
source elements. data-ogpreview=0 excludes the element from being included
in the preview. Positive numbers set the preview priority. The lowest
value found is chosen first.
