What's the impact on the closure size? Increase, yes, but how much? Could it be reduced by using konqueror or another Qt or KDE integrated browser?

I think Konqueror has become a little outdated in recent years. If we want a KDE browser by default, I would recommend Falkon. It uses Chromium's Blink rendering engine (qtwebengine) so is closer to a modern web browser. If this seems reasonable, I would recommended just including it in the Plasma5 module (https://github.com/NixOS/nixpkgs/blob/master/nixos/modules/services/x11/desktop-managers/plasma5.nix).

What's nice about Firefox is I think it's what most people are going to be installing anyway. It appears to be a pretty modest increase. Less than 100MB,

without firefox:

$ nix-build -E '(import "${builtins.fetchTarball "https://github.com/NixOS/nixpkgs/archive/bd13ef5944a01f02006bcd4caafaaeba6a52d323.tar.gz"}/nixos/release.nix" {}).ova'
/nix/store/7w5gs9pinc4lmyc4bhm80mivrsf9p186-nixos-ova-19.03pre130979.gfedcba-x86_64-linux
$ du /nix/store/7w5gs9pinc4lmyc4bhm80mivrsf9p186-nixos-ova-19.03pre130979.gfedcba-x86_64-linux/*.ova
1052420	/nix/store/7w5gs9pinc4lmyc4bhm80mivrsf9p186-nixos-ova-19.03pre130979.gfedcba-x86_64-linux/nixos-19.03pre130979.gfedcba-x86_64-linux.ova

with firefox:

$ nix-build -E '(import "${builtins.fetchTarball "https://github.com/NixOS/nixpkgs/archive/94bec239d56a0184629ce0cb95e4f6efcc835772.tar.gz"}/nixos/release.nix" {}).ova'
/nix/store/xn777j69y6qh802ngif1hvk7jh3f6q6z-nixos-ova-19.03pre130979.gfedcba-x86_64-linux
$ du /nix/store/xn777j69y6qh802ngif1hvk7jh3f6q6z-nixos-ova-19.03pre130979.gfedcba-x86_64-linux/*.ova
1119636	/nix/store/xn777j69y6qh802ngif1hvk7jh3f6q6z-nixos-ova-19.03pre130979.gfedcba-x86_64-linux/nixos-19.03pre130979.gfedcba-x86_64-linux.ova

Hmm, I had assumed konqueror was in the image already; perhaps it's changed over the years. In any case, I personally don't expect the installation images really need to contain a "top-tier" browser, but we certainly should have a decent browser in there (and I don't mean a text-mode one like for the minimal images).

@oxij: that diff shows firefox on both left and right sides.

Ok I missed that in the installation CD. I think we also want it Firefox in the VirtualBox image though.

Personally, I would prefer different DEs using their official or de-facto official browsers by default. To me qutebrowser feels preferable for KDE. (Especially because the "official" firefox build has telemetry, "studies" and portal-detect enabled by default, all of which seem pretty evil to me, and qutebrowser does nothing of the sort.) I didn't try GNOME3 and have no idea what is the default browser there, but I remember using midori under MATE/Cinnamon and it was ok for simple browsing too.

So I think there is some confusion here because profiles/graphical.nix & installer/cd-dvd/installation-cd-graphical-base.nix do almost the exact same thing. The main difference is one is going into the .iso and the other into the .ova. It seems like we should refactor to avoid duplication here. I'm tracking this in #47256.

Anyway since Firefox was added in #20433, I am considering this just an oversight and something that can be merged right away.

100 MB seems like a pretty significant increase in closure size. The installation ISOs are already way too bloated. IMHO Konqueror should be sufficient for reading the manual.

That reminded me... that a week ago I noticed that the 18.09 minimal ISO has overgrown my old 512 MiB flash drives :-) (by a few megabytes; 18.03 fits) Well I guess people don't commonly use such small drives anymore, so the exact threshold probably isn't that significant, but there's certainly room for improvement in the sizes of minimal images as well.

I think consistency between .ova and .iso is good to have. I agree that we should work on making these smaller. We end up pulling in GCC, Qt4, LLVM lib, etc. There is lots of room for improvements.

#47292