I am reading and taking notes on the HTML specifications for 100 days as part of #The100DayProject. Read the initial intent/backstory. I am a Microsoft employee but all opinions, comments, etc on this site are my own. I do not speak on behalf of my employer, and thus no comments should be taken as representative of Microsoft's official opinion of the spec. Subsections not listed below were read without comment.
Currently reading in 2.7 Common DOM Interfaces.
2.7 Common DOM Interfaces
IDL = interface definition language
"If a reflecting IDL attribute is a DOMString attribute whose content attribute is defined to contain one or more URLs" What attribute would that be? First thing that springs to mind is srcset, but that string also contains commas and size information. Not just space-separated URLs, which is what this section would imply. Add to the list of questions!