Flatpak, Snap & pacman

An AppImage fails to launch on Ubuntu 22.04 or later — what's the usual cause and fix?

How does an AppImage differ from Snap and Flatpak in what it needs to run and distribute?

What do you give up by choosing AppImage over Snap or Flatpak, and how do you update one?

What problem do Flatpak and Snap solve that conventional DEB/RPM package management doesn't, and who backs each?

A user expects to apt install or dnf install LibreOffice on Fedora, or Firefox on Ubuntu, and is surprised — what's going on?

How is Arch Linux's pacman structured differently from apt/dnf, and what do its package files look like?

In pacman's option scheme, which single letters install, remove, query installed packages, and search — and what does -Syu do?

You run pacman -S on a package that's already at the current version — what happens, and how do you avoid it?

What is the Arch User Repository (AUR), and why can't pacman update packages installed from it?

What does an AUR helper like yay give you over plain pacman?

Your Arch disk is filling with cached packages — what's the difference between pacman -Sc and pacman -Scc?

Package management usually keeps software current — so why does a BIOS/EFI or CPU firmware update fall outside it, and what initiative fixed that on Linux?

Which fwupdmgr subcommands refresh metadata, list updatable hardware, and apply firmware updates?

What can go wrong when fwupd applies an EFI update, and what does UEFI Secure Boot additionally require?

If a CPU microcode update isn't written into the package system, where does it live — and what happens at each boot?

Microcode updates work out of the box on most distributions — why doesn't that hold on Arch Linux?

What do Flatpak and Snap change about the privileges and isolation of installing a desktop app?

Why do Flatpak and Snap apps consume far more disk and RAM than the same program installed conventionally?

A fresh Flatpak setup shows no apps to install (flatpak remotes is empty) — what's missing and how do you fix it?

Which flatpak subcommands install, list, update, and remove apps — and where do the files actually land?

Mechanically, how does snapd make a snap file's application available in the filesystem?

Which snap subcommands install, list, run, update, and remove packages — and what update behavior differs on Ubuntu?

What's the fundamental distribution difference between where Snaps and Flatpaks can come from?

Which per-user background process must be running for Flatpak apps to work, and how is it started?

Why does Snap's disk usage roughly double over time on Ubuntu, and how do you trim it back?

What are pacman's default package repositories, and where are they configured?

How does Linux Mint handle Snap and Flatpak differently from its Ubuntu base?

Besides running it, how can you unpack or inspect the contents of an AppImage?

Manjaro uses Arch's pacman — so how does its package setup differ from plain Arch?

What makes Pop!_OS's package and boot setup diverge from stock Ubuntu?

How do immutable Linux distributions like Fedora Silverblue apply updates without a writable root?

What is PackageKit, and why is its future considered bleak despite being useful?

Why does pkcon fail if you run it as root, and when does packagekitd actually run?

PackageKit has silently eaten several GiB of disk — where, and how do you reclaim it?

In pacman, which -Q variants show a package's details, its files, and which package owns a given file?

pacman -R leaves orphaned dependencies behind — which option removes them too?

pacman or yay suddenly refuses with a 'package signature is marginal trust' error — cause and fix?

After flatpak uninstall, the app's settings survive a reinstall — why, and how do you wipe them?