Actually I’m asking: how often does the nixpkgs files be released to unstable channel?
I find that the .nix file of the electron pkg in my machine is outdated so I run the update commands: nix-channel --update && nixos-rebuild switch --upgrade --verbose several times, but no update happened.
You can check out [1] to know from when the bump was. Currently it’s
lagging behind quite a lot, if I understood correctly it’ll soon move
forwards.
Then, the commands you mention are not for updating the .nix file of the electron pkg in your machine, they are for updating your whole machine
so that it matches the state of the nixpkgs repository at the commit
of the channel (that is indicated on [1]). This maybe matches your
expectations (ie. if the electron package indeed got an update in nixpkgs before the last channel bump), and maybe not (eg. if it hasn’t).
Anyway, running it more than once should have no effect.
What it would take would be to make it a nixos.org subdomain is the person operating nixos.org to either do some DNS configuration, or host their own instance (the DNS configuration seems the simplest).
However, the reason I have not tried to do it so far is that howoldis is hard to read, the underlying process is hard to understand (or was, last time I looked at it), and as a result, I find that it gives an underserved negative view of the whole thing.