You cannot access the help icon buttons on /job/*/configure pages using either
the TAB key or numbers when using the Firefox Mouseless Browsing (MLB)
extension. A plain HTML <img> has no KB accessibility as the browser does not
consider it a real button; it is only made to act like one due to

.help-button {
cursor: pointer;
}

and

".help" : function(e) {
e.onclick = function()

}

I tried using <input type="image" .../> but could not get this to work; I could
get the page to display the help but then the browser would try to submit the
form action. Nor could I get a satisfactory result wrapping the <input> in a
<form>; not sure how to completely disable a <form> from doing anything except
where told by onclick. Setting onsubmit for the form did not help; it still
tried to load a new page. One of those days I'm glad I'm not paid to write web
apps...