arc-unpacker: rename from arc_unpacker

pkgs/by-name/ar/arc-unpacker/package.nix

@@ -17,7 +17,7 @@
 }:
 
 stdenv.mkDerivation {
-  pname = "arc_unpacker";
+  pname = "arc-unpacker";
   version = "0.11-unstable-2021-09-06";
 
   strictDeps = true;

pkgs/top-level/aliases.nix

@@ -332,6 +332,7 @@ mapAliases {
   arangodb = throw "arangodb has been removed, as it was unmaintained and the packaged version does not build with supported GCC versions"; # Added 2025-08-12
   arc-browser = throw "arc-browser was removed due to being unmaintained"; # Added 2025-09-03
   arc-theme = throw "'arc-theme' has been removed because it depended on 'gtk-engine-murrine', which was removed because it was unmaintained upstream and depended on GTK 2."; # Added 2026-07-22
+  arc_unpacker = throw "'arc_unpacker' has been moved to 'arc-unpacker'"; # Added 2026-07-28
   archi = throw "'archi' has been removed, since its upstream maintainers do not want it packaged"; # Added 2025-11-18
   archipelago-minecraft = throw "archipelago-minecraft has been removed, as upstream no longer ships minecraft as a default APWorld."; # Added 2025-07-15
   ArchiSteamFarm = warnAlias "ArchiSteamFarm has been renamed to/replaced by 'archisteamfarm'" archisteamfarm; # Added 2026-01-31