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?

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