In the details element, from section 4.11
, my understanding is that the <summary> element may only contain phrasing content, and therefore may not
contain elements such as headers, or other such block content. I'm concerned that this is an unnecessary constraint that will result in people either not using the feature, or using it in a way that results in ignored validation errors. I would therefore like to suggest that the <summary> element definition be amended to accept more content than it does today, while keeping its current behavior of showing the element's other contents when clicked.