In thinking and reasoning about the new question navigation bar and trying to figure out where unnecessary and necessary redundancies are and what could be improved, I more often than not stumble across the problem that I don't really know what all those different options actually do, and neither of the two iterations of that official announcement question seems to completely explain it. I feel that any further question I'd ask might simply be an XY problem of not knowing what I want to improve at all. It might be clear to people deeply acquainted with the old navigation bar already what e.g. "recommended" actually means, but there are also other sub-options that seem to confuse people.
So hands down, what are the exact technical criteria (i.e. votes/answers/views whatever) that all the different tabs and their filtering/showing sub-options employ for filtering questions? I know what the tag filters do, or what the time filters in the "popular" tabs do, but especially some "show" options are a bit unclear to me, and others might be clear but I'd still like to have it canonically answered to be sure. In particular I'm having problems grasping the following options:
show: recommended- That doesn't seem to filter only my favourite tags (for which there's a separate filter anyway), so what is recommended at all?
sort: hot- Does this use the "arbitrary hotness points" of the HNQ or another hotness formula, or even other criteria in addition?
"need answer" tab
show: need answervs
show: no answer- I figure those are the good old "no accepted/upvoted answers" vs "no answer at all" options. But do they use additional criteria? I'm asking because some of the various "unanswered" views in the old design had the unexpected behaviour of excluding negatively voted questions.
show: all- What does this actually show? It seems to include questions with accepted answers, but how does it then differentiate from the
show: allview in the "new" tab? Or maybe this even is absolutely intentional redundancy for easier usability?