What is a “jobset” in the parlance of the Hydra continuous integration tool?

Solution for What is a “jobset” in the parlance of the Hydra continuous integration tool?
is Given Below:

I found definitions (see below) and how they are usually used (i.e., a Hydra jobset is tracking a git branch) but I still couldn’t figure out what they are in the general sense. Maybe if you could explain it laymen’s terms with specific examples?

  • Eelco Dolstra, Eelco Visser: “Hydra: A Declarative Approach to Continuous Integration

    a specification of the location of a Nix expression, along with possible values for the function arguments of the jobs defined by the Nix expression.

  • NixOS Wiki: “Hydra

    Job Set

    A list of jobs which will be run. Often a Jobset fits to a certain branch (master, staging, stable). A jobset is defined by its inputs and will trigger if these inputs change, e.g. like a new commit onto a branch is added. Job sets may depend on each other

  • Hydra User’s Guide

    3.2 Job Sets

    A project can consist of multiple job sets (hereafter jobsets), separate tasks that can be built separately, but may depend on each other (without cyclic dependencies, of course).

My question may seem pointless after listing all these definitions, but here’s an examle to demonstrate my confusion: I looked at the project listing at https://hydra.nixos.org/ and I was under the impression that a project is a channel, and jobsets are the branches in a repo. (I know, there is no mention of “channel” in there, and on the channel page it even says that Nix channels are not supported by this Hydra server. 🙂
I could fool myself with that when looking at the Hydra project but this argument fell apart when I clicked on the flakes one (that is, couldn’t find a supporting github repo, but generally the jobset names didn’t feel like branch names).

Also, in the Dolstra/Visser paper, Hydra was set up using SVN; I don’t know if SVN even uses branches (mostly because the paper didn’t mention them) but this does prove that Hydra can be set up with VCS/SCM other than git where the underlying concepts can be fundamentally different. Again, I could easily be wrong.