Change:
<ins> { _7zz , buildDotnetModule , copyDesktopItems , desktop-file-utils , dotnetCorePackages , fetchFromGitHub , fontconfig , lib , libICE , libSM , libX11 , nexusmods-app , runCommand , enableUnfree ? false # Set to true to support RAR format mods }: let _7zzWithOptionalUnfreeRarSupport = _7zz.override { inherit enableUnfree; }; in buildDotnetModule rec { pname = "nexusmods-app"; version = "0.4.1"; src = fetchFromGitHub { owner = "Nexus-Mods"; repo = "NexusMods.App"; rev = "v${version}"; fetchSubmodules = true; hash = "sha256-FzQphMhiC1g+6qmk/R1v4rq2ldy35NcaWm0RR1UlwLA="; }; projectFile = "NexusMods.App.sln"; nativeBuildInputs = [ copyDesktopItems ]; nugetDeps = ./deps.nix; dotnet-sdk = dotnetCorePackages.sdk_8_0; dotnet-runtime = dotnetCorePackages.runtime_8_0; preConfigure = '' substituteInPlace Directory.Build.props  --replace '</PropertyGroup>' '<ErrorOnDuplicatePublishOutputFiles>false</ErrorOnDuplicatePublishOutputFiles></PropertyGroup>' ''; postPatch = '' ln --force --symbolic "${lib.getExe _7zzWithOptionalUnfreeRarSupport}" src/ArchiveManagement/NexusMods.FileExtractor/runtimes/linux-x64/native/7zz ''; makeWrapperArgs = [ "--prefix PATH : ${lib.makeBinPath [desktop-file-utils]}" "--set APPIMAGE $out/bin/${meta.mainProgram}" # Make associating with nxm links work on Linux ]; runtimeDeps = [ fontconfig libICE libSM libX11 ]; executables = [ nexusmods-app.meta.mainProgram ]; doCheck = true; dotnetTestFlags = [ "--environment=USER=nobody" (lib.strings.concatStrings [ "--filter=" (lib.strings.concatStrings (lib.strings.intersperse "&" ([ "Category!=Disabled" "FlakeyTest!=True" "RequiresNetworking!=True" "FullyQualifiedName!=NexusMods.UI.Tests.ImageCacheTests.Test_LoadAndCache_RemoteImage" "FullyQualifiedName!=NexusMods.UI.Tests.ImageCacheTests.Test_LoadAndCache_ImageStoredFile" ] ++ lib.optionals (! enableUnfree) [ "FullyQualifiedName!=NexusMods.Games.FOMOD.Tests.FomodXmlInstallerTests.InstallsFilesSimple_UsingRar" ]))) ]) ]; passthru = { tests = { serve = runCommand "${pname}-test-serve" { } '' ${nexusmods-app}/bin/${nexusmods-app.meta.mainProgram} touch $out ''; help = runCommand "${pname}-test-help" { } '' ${nexusmods-app}/bin/${nexusmods-app.meta.mainProgram} --help touch $out ''; associate-nxm = runCommand "${pname}-test-associate-nxm" { } '' ${nexusmods-app}/bin/${nexusmods-app.meta.mainProgram} associate-nxm touch $out ''; list-tools = runCommand "${pname}-test-list-tools" { } '' ${nexusmods-app}/bin/${nexusmods-app.meta.mainProgram} list-tools touch $out ''; }; updateScript = ./update.bash; }; meta = { description = "Game mod installer, creator and manager"; mainProgram = "NexusMods.App"; homepage = "https://github.com/Nexus-Mods/NexusMods.App"; changelog = "https://github.com/Nexus-Mods/NexusMods.App/releases/tag/${src.rev}"; license = [ lib.licenses.gpl3Plus ]; maintainers = [ lib.maintainers.l0b0 ]; platforms = lib.platforms.linux; }; } </ins>

Discussion:
Project description From the : Metadata homepage URL: source URL: license: gpl3 platforms: linux (the says tests run on OSX, but I can't find the build instructions) Priorities Add a :+1: [reaction] to [issues you find important]. [reaction]: [issues you find important]: