Questions about the binary repositories

[Robert Bagdan <kikadf.01%gmail.com@localhost>]

I have a few questions regarding the NetBSD pkgsrc binary repositories.
There is the pkgsrc repository, which has the -trunk and the -quarterly
(currently pkgsrc-2025Q3) branches. The binary repository is built from the
current quarterly branch. I also see on the bulktracker that bulk builds are
run from time to time for different OS/architecture/pkgsrc branch combinations.

My questions are:
1) Are the bulk builds automatic or manually triggered? What’s the
    rule, how often are they started?
2) Do these builds run on dedicated build servers, or on developers’
    own machines?
3) Where are the binary packages from pkgsrc trunk/current/HEAD bulk
     builds, are they available anywhere?
4) How often are updated packages from pkgsrc incorporated into the
    quarterly binary repositories? Is there any automation involved, or
    does it require manual intervention?
5) When a change is made in the quarterly branch, are only the
     modified packages rebuilt, or is the entire set rebuilt?
6) After the recent curl update, I noticed that pkgin updated packages
     from the quarterly binary repo that depended on curl, even though
     their PKGREVISION hadn’t changed.
    How did pkgin know to update those as well?

-- 
Regards,
kikadf