[Solved] Confusion with APT sources list

[TJI]

Hi! My system is Debian Stable, installed from Xfce Live. My question is about deb-src in /etc/apt/sources.list. I decided to try backports-kernel, and followed these instructions:

https://forums.debian.net/viewtopic.php?t=159363

According to this, "New(ish) hardware may also require more current firmware. Check if a backports version is available and install it. If not, it is normally safe to install newer firmware packages from Testing or Unstable but do not add those as sources. Rather download the required package and install manually."

Have I understood correctly that it means adding "deb-src"-line? If so, can I get explanation why not? What harm can it cause?

Because when I was about to modify my sources list, I found out that those both lines were there already, and I confirmed that by default install from Xfce Live Stable creates list like this:

# See https://wiki.debian.org/SourcesList for more information.
deb http://deb.debian.org/debian bookworm main non-free-firmware
deb-src http://deb.debian.org/debian bookworm main non-free-firmware

deb http://deb.debian.org/debian bookworm-updates main non-free-firmware
deb-src http://deb.debian.org/debian bookworm-updates main non-free-firmware

deb http://security.debian.org/debian-security/ bookworm-security main non-free-firmware
deb-src http://security.debian.org/debian-security/ bookworm-security main non-free-firmware

# Backports allow you to install newer versions of software made available for this release
deb http://deb.debian.org/debian bookworm-backports main non-free-firmware
deb-src http://deb.debian.org/debian bookworm-backports main non-free-firmware

So should I remove the last entry, and if yes, then why is it added by default?

Thank you in advance!

[sunrat]

deb-src lines are there to enable installing source packages of software. You would only need that if you compile Debian packages from sources. Most people don't do that so only require the deb lines to install deb packages which are already compiled.
If you don't compile software from Debian sources, just comment out the deb-src lines with a # eg.:

Code: Select all

# deb-src http://deb.debian.org/debian bookworm main non-free-firmware

Doing that will save a little time when running apt update.

[TJI]

So even with that deb-src-line enabled it does not actually do anything automatically with normal updating unless I intentionally command so, e.g. I would like to download/update sources for various purposes?

And thank you for speedy response, I appreciate it.

[Hallvor]

No, you just waste a little time and bandwidth. Unless you want to build something from source, just comment them out.

[TJI]

Thank you for your clarifications, this is clear to me now. I'll mark this solved.