If these questions are already answered somewhere in this forum, please forgive my lack of search skills and post the link(s) to the existing post(s) that have the information.  I did try, honestly, and found out some of the answers, but not all of them.

I'm a moderator on a private tracker, but I have no access to a box where I can run KTorrent and find out these answers for myself.

To go by what my searches in this forum did turn up, the following appear to be true; please correct me gently if they aren't:

It seems from my searches in this forum that, as of version 2.0 and in all releases since then ...

1. KTorrent will fall back to DHT on a torrent that names a central tracker if the tracker is unavailable or unresponsive, unless the torrent is private.
2. KTorrent will not allow peer exchange on a private torrent.

Are both of those correct?

Now, here's the question to which I could not find an answer: what makes KTorrent consider a torrent private?

Is it the 7:privatei1e key in the info dictionary?

Does KTorrent also honor the private=1 tracker response, if the 7:private1ie key is not in the info dictionary? (µTorrent 1.2.0 did; BitComet claimed to honor the tracker response but didn't, even if the 7:privatei1e key was also in the info dictionary, at least back in the days of BitComet 0.59 and 0.60.)

And are there any differences in those answers for various releases of KTorrent since 2.0, or have they been the same and remained unchanged from version to version?

Thank you all for any assistance.

DHT and PEX are both disabled for private torrents, and this has been the case ever since these features have been added.

And a private torrent is a torrent with a private key in the info part of the torrent.

We don't check for private flags returned by the tracker. I wasn't even aware that some trackers did this,

George wrote:DHT and PEX are both disabled for private torrents,

Yes, so I'd seen.

Then he wrote:and this has been the case ever since these features have been added.

And a private torrent is a torrent with a private key in the info part of the torrent.

We don't check for private flags returned by the tracker.

That's what I wanted to know, and in fact those three answers are exactly the ones I had assumed.  Thank you very much.

The private=1 tracker response seems like a highly unreliable way of marking a torrent private to me.... I mean, if the tracker can't be contacted initially for any reason, then clients will start announcing themselves on DHT.

Jdong: that is surely among the reasons that Ludde dropped support for it from µTorrent.  Version 1.2.0 honored it but releases from 1.2.1 onward have not.