What is column 3 (suite/release/distribution) in /etc/apt/sources.list?

Question

I'm confused what the value of column 3 ("suite" or "release" or "distribution") is supposed to be in Ubuntu's /etc/apt/sources.list.

From man sources.list (edited for relevance):

The format for two one-line-style entries using the deb and deb-src types is:

deb [ option1=value1 option2=value2 ] uri suite [component1] [component2] [...]
deb-src [ option1=value1 option2=value2 ] uri suite [component1] [component2] [...]

suite can specify an exact path, in which case the components must be omitted and suite must end with a slash...If suite does not specify an exact path, at least one component must be present.

suite may also contain a variable, $(ARCH) which expands to the Debian architecture (such as amd64 or armel) used on the system.

From https://wiki.debian.org/SourcesList (where column 3 seems to be called the "distribution"):

The 'distribution' can be either the release code name / alias ( stretch, buster, bullseye, bookworm, sid) or the release class (oldoldstable, oldstable, stable, testing, unstable) respectively. If you mean to be tracking a release class then use the class name.

From https://help.ubuntu.com/community/Repositories/CommandLine (edited for relevance):

Typically.../etc/apt/sources.list looks like this:

deb http://ch.archive.ubuntu.com/ubuntu/ saucy main restricted
deb-src http://ch.archive.ubuntu.com/ubuntu/ saucy main restricted

...
saucy is the release name or version of your distribution.
...
For other Ubuntu releases you would replace the 'saucy' with the current version you have installed ('precise', 'quantal', 'raring', 'saucy', 'trusty', ...) Type lsb_release -sc to find out your release.

According to lsb_release -sc, my suite/release/distribution is "jammy":

$ lsb_release -sc
jammy
$

My question is: given that my suite/release/distribution is "jammy", which is apparently be the value that should be used in column 3, why do some entries in /etc/apt.sources.list file have column 3 values of jammy-security, jammy-updates and jammy-backports?

$ cat /etc/apt/sources.list
# See http://help.ubuntu.com/community/UpgradeNotes for how to upgrade to
# newer versions of the distribution.
deb http://archive.ubuntu.com/ubuntu/ jammy main restricted
# deb-src http://archive.ubuntu.com/ubuntu/ jammy main restricted

## Major bug fix updates produced after the final release of the
## distribution.
deb http://archive.ubuntu.com/ubuntu/ jammy-updates main restricted
# deb-src http://archive.ubuntu.com/ubuntu/ jammy-updates main restricted

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team. Also, please note that software in universe WILL NOT receive any
## review or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu/ jammy universe
# deb-src http://archive.ubuntu.com/ubuntu/ jammy universe
deb http://archive.ubuntu.com/ubuntu/ jammy-updates universe
# deb-src http://archive.ubuntu.com/ubuntu/ jammy-updates universe

## N.B. software from this repository is ENTIRELY UNSUPPORTED by the Ubuntu
## team, and may not be under a free licence. Please satisfy yourself as to
## your rights to use the software. Also, please note that software in
## multiverse WILL NOT receive any review or updates from the Ubuntu
## security team.
deb http://archive.ubuntu.com/ubuntu/ jammy multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ jammy multiverse
deb http://archive.ubuntu.com/ubuntu/ jammy-updates multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ jammy-updates multiverse

## N.B. software from this repository may not have been tested as
## extensively as that contained in the main release, although it includes
## newer versions of some applications which may provide useful features.
## Also, please note that software in backports WILL NOT receive any review
## or updates from the Ubuntu security team.
deb http://archive.ubuntu.com/ubuntu/ jammy-backports main restricted universe multiverse
# deb-src http://archive.ubuntu.com/ubuntu/ jammy-backports main restricted universe multiverse

deb http://security.ubuntu.com/ubuntu/ jammy-security main restricted
# deb-src http://security.ubuntu.com/ubuntu/ jammy-security main restricted
deb http://security.ubuntu.com/ubuntu/ jammy-security universe
# deb-src http://security.ubuntu.com/ubuntu/ jammy-security universe
deb http://security.ubuntu.com/ubuntu/ jammy-security multiverse
# deb-src http://security.ubuntu.com/ubuntu/ jammy-security multiverse

The column 3 values in my sources.list do not appear to be an exact path, nor do they have a variable, and does not appear to be a release class, so I think those respective sections from man sources.list and the Debian wiki do not apply. But I don't see any description on the suite/release/distribution "suffixes" (for my lack of knowing the correct thing to call it) like "-updates", "-security", or "-backports".

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If related: please explain if the terms "suite," "distribution," and "release" are used interchangeably in this context, or if there's a meaningful difference between them. From the answers to this question, I thought I'd reached the understanding that "distribution" meant Ubuntu vs. Debian vs. Fedora, etc., so its use in this context (specifically, the Debian wiki) has clouded the understanding I thought I'd reached.

Answer 1

Definitions

1. Suite - See Definition 2e.
2. Release - See Stages of Development.
3. Distribution - See the paragraph RE: Distro.

In Relation to APT

1. jammy-* would be considered a "suite" as all the tools in the suite apply to the name given to them. Read the comments above the entries.
   • Security has no comments as this contains critical bugfixes to base software, and it's expected that if a security issue is affecting a user, it's the user's responsibility to check the maintainer's bug reporting system, as the fix will be applied whether the user is affected or not.
   • Backports contains newer versions of software, that isn't checked for security issues
   • Updates includes updates to packages that were installed in the base system, i.e glibc, bash etc, that are checked for security issues.
2. jammy itself is the Release. See also: Jammy Jellyfish
3. Ubuntu is the Distribution.

Think of it in Stages, and the following sentence will illustrate the stages: The Distribution Ubuntu contains the current Release jammy, which contains multiple suites.

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In relation to the sources file:

• deb refers to the package type, and in most cases installs the binary/executable. Can also be deb-src, which will install the source code.
• http://... refers to the URI.
• main refers to the branch to download from.
• restricted refers to upload privileges, i.e., only approved software can be uploaded to the repository, thus plain users are restricted to download only. Can also refer to licensing, i.e., non free software.