This feature allows you to set alternatives [1].
For example, like this:

   @$(call add,ALTERNATIVES,/usr/bin/xvt:/usr/bin/xterm)

Also, in the config itself, targets for setting alternatives may already
be predefined. For example, use/alternatives/xvt/% allows you to specify
arbitrary alternatives for xvt:
use/alternatives/xvt/xterm, use/alternatives/xvt/mate-terminal, etc.
However, an alternative must be available.

1. https://www.altlinux.org/Alternatives

After 50-users script from deflogin

Request by Speccyfighter

Fixed a bug with moving the core in a cycle. This only needs to be
done once.

These SBC is not available for me.

Request by mcpain@. Needed mdmon for Intel VROC support.

Made at the request of Evgeny Sinelnikov <sin@altlinux.org>
This patch was co-authored by Anton Midyukov.

Needed to install a minimal system
on the root partition with btrfs

If udev-rule-generator-net is installed on the system, add the interface
naming rules from this package to the initrd. If not, add the standard
udev rules.

The naming conventions for network interfaces on stage1 and stage2 must match.
See also commit: 1190de27

Request by Speccyfighter with forum.altlinux.org

When unpacking squash into multiple partitions using unsquashfs,
hardlinks are not converted to files and an unpacking error occurs.
See also: https://bugzilla.altlinux.org/45329

To manage rpm packages.
See also: https://bugzilla.altlinux.org/show_bug.cgi?id=45377

Need for debug alterator-vm.
Request by mcpain@

installer-distro-altlinux-desktop does not develop and there is no
desire to support it. It will also allow to check the
alt-workstation profile on regulars, additional testing.

When installing with a classic installer, this package is also needed.

Not needed when installing with a classic installer.

This feature complements the live image of the second stage with installation
image-specific settings and scripted hooks.

It is recommended to connect using +live-installer to ensure that a typical set
of installer-related features is included.

Unlike the install2 feature, a separate image of the second stage of 'altinst'
is not built, but the live image is supplemented with installer packages in
order to reduce the total volume of the iso image.

Installation consists of two stages:
1. The live image is unpacked, as in livecd-install
2. Install additional packages BASE_PACKAGES and package groups THE_GROUPS as in install2.

Unlike install2, only those packages that are not in the live image are placed in the main repository. This is how the size of the iso image is reduced.

not needed for linux kernel >5.4