Right, but opening from the keyboard is only a tiny fraction of what is needed. If I tab around on the display, I get a bunch of buttons that are likely column

Right, but opening from the keyboard is only a tiny fraction of what is needed. If I tab around on the display, I get a bunch of buttons that are likely column headers (I.e. "Status", "Transferred", etc.) but I never reach a list of actual requests through which I can arrow. I press Space on a button labeled "Start performance analysis" which immediately plunks focus into a text field from which I can't seem to escape. The entire developer tools interface is littered with these sorts of inconsistencies. The HTML inspector is similar. I can pull up a tree of elements, but sometimes I can expand tree levels from the keyboard and sometimes I can't. I've taken to using the context menu to copy an element's inner HTML into a text editor, then inspecting it that way. Often, clicking Inspect Element from the context menu doesn't open the inspector with keyboard focus on the element I'm inspecting, either, which is a massive pain when I'm trying to tell a developer what is needed to make a site accessible. So, IOW, I can't even file actionable bug reports for web apps without putting forth lots of effort to even identify the element that is at fault.