@nschonni - believe it not , I do not agree. suffix is really bound to that. a suffix. The function was a called getMode() and to be a bit future forward I have a tendency to leave the variable as $mode for developers to understand that is how vapour is detecting the mode. If  at a later date we start to incorporate more that just a suffix as a setting for what mode we are in. (i.e - stylesheets, or development environments through document.location ) then suffix becomes part of the equation not so much the mode flag. I agree that right now it is just simply detecting a suffix, but the variable could potentially grow.