Describe the bug

After updating to @sveltejs/kit@2.53.3, this is logged on vite build:

Unknown output options: codeSplitting. Allowed options: amd, assetFileNames, banner, chunkFileNames, compact, dir, dynamicImportInCjs, entryFileNames, esModule, experimentalMinChunkSize, exports, extend, externalImportAssertions, externalImportAttributes, externalLiveBindings, file, footer, format, freeze, generatedCode, globals, hashCharacters, hoistTransitiveImports, importAttributesKey, indent, inlineDynamicImports, interop, intro, manualChunks, minifyInternalExports, name, noConflict, onlyExplicitManualChunks, outro, paths, plugins, preserveModules, preserveModulesRoot, reexportProtoFromExternal, sanitizeFileName, sourcemap, sourcemapBaseUrl, sourcemapDebugIds, sourcemapExcludeSources, sourcemapFile, sourcemapFileNames, sourcemapIgnoreList, sourcemapPathTransform, strict, systemNullSetters, validate, virtualDirname

Reproduction

• https://github.com/hyunbinseo/svelte-kit-templates/tree/svelte-kit-15442
• hyunbinseo/svelte-kit-templates@40be215

Logs

System Info

System:
  OS: Windows 11 10.0.26200
  CPU: (8) x64 Intel(R) Core(TM) Ultra 7 258V
  Memory: 7.89 GB / 31.48 GB
Binaries:
  Node: 24.14.0 - C:\Users\hyunb\AppData\Local\fnm_multishells\34776_1772152521906\node.EXE
  npm: 11.9.0 - C:\Users\hyunb\AppData\Local\fnm_multishells\34776_1772152521906\npm.CMD
  pnpm: 10.30.1 - C:\Users\hyunb\AppData\Local\fnm_multishells\34776_1772152521906\pnpm.CMD
  Deno: 2.4.0 - C:\Users\hyunb\.deno\bin\deno.EXE
Browsers:
  Chrome: 145.0.7632.117
  Edge: Chromium (140.0.3485.54)
  Firefox: 147.0.4 - C:\Program Files\Mozilla Firefox\firefox.exe
npmPackages:
  @sveltejs/adapter-auto: ^7.0.1 => 7.0.1
  @sveltejs/kit: ^2.53.3 => 2.53.3
  @sveltejs/vite-plugin-svelte: ^6.2.4 => 6.2.4
  svelte: ^5.53.2 => 5.53.2
  vite: ^7.3.1 => 7.3.1

Severity

annoyance

Additional Information

No response