Accessible name for row headers is incorrect
Both the expand button and the code element in the row header cells in the tables are inline so the text gets concatenated without a space between in the accessible name calculation. (at least it does in FF anyway - you can check in the DOM inspector)
So my row header is "expandarticle"
Either add a space or make one of the elements a block level element.
See https://github.com/stevefaulkner/HTML5accessibility/issues/26#issuecomment-212983061
It has a space between in Edge at least. Will look into FF. But i'm not sure it is a great (or correct) experience for the a11yName to be expand/collapse [element name]. I'm not sure a way around that though as the button needs to be in the table cell.
The whole expandable area needs looked at as this is just initial implementation to get it in a place where it can be tested.