As a child you would wait. And watch from far away. But you always knew that you'd be the one that work while they all play. In youth you'd lay awake at night and scheme. Of all the things that you would change, but it was just a dream! Here we are.
A whitelist is a list or register of entities that provide a particular privilege, service, mobility, access or recognition. Entities on the list will be accepted, approved and/or recognized. Whitelisting is the reverse of blacklisting, the practice of identifying entities that are denied, unrecognised, or ostracised.
And so on, plus several other variations, plus every combination of every variation. The more I investigate, the more cases I find where Internet Explorer for Windows will treat seemingly innocuous markup as code and blithely execute it. This is why Universal Feed Parser uses a whitelist and not a blacklist. I am reasonably confident that none of the elements or attributes on the whitelist are security risks. I am not at all confident about elements or attributes that I have not explicitly investigated.