The TopicViewResultExecutor can, optionally, determine what view to display based on the HTTP Accept header. If there are multiple values, however, it is currently only operating off of the first value. In practice, there are almost always multiple headers, and it should iterate over these.

Further, the current logic also doesn't support composite values which contain additional metadata, such as e.g. text/html;level=2;q=0.5. While these headers are uncommon, at least for our needs, they should remain "supported" by stripping out this additional metadata. (Our code needn't attempt to prioritize based on duplicate values with different metadata.)