diff --git a/packages/desktop/electron-builder.config.test.ts b/packages/desktop/electron-builder.config.test.ts
index 6e773dd1d58..256a3bb2a3c 100644
--- a/packages/desktop/electron-builder.config.test.ts
+++ b/packages/desktop/electron-builder.config.test.ts
@@ -91,6 +91,11 @@ for (const channel of channels) {
         "js-yaml/dist/js-yaml.min.js",
         "js-yaml/dist/js-yaml.mjs.map",
         "js-yaml/bin/js-yaml.js",
+        "unrelated/dist/index.js.map",
+        "unrelated/dist/index.cjs.map",
+        "unrelated/dist/index.d.ts",
+        "unrelated/dist/index.d.cts",
+        "unrelated/dist/index.d.ts.map",
       ]) {
         expect(filter(path.join(import.meta.dirname, prefix, file), statSync(import.meta.filename))).toBe(false)
       }
@@ -112,7 +117,10 @@ for (const channel of channels) {
         "js-yaml/lib/loader.js",
         "js-yaml/dist/js-yaml.mjs",
         "debug/src/index.js",
-        "unrelated/dist/index.js.map",
+        "unrelated/dist/index.js",
+        "unrelated/dist/index.cjs",
+        "unrelated/dist/data.json",
+        "unrelated/src/index.ts",
         ...["@zip.js/zip.js", "electron-updater", "builder-util-runtime", "ajv", "ajv-formats", "js-yaml"].flatMap(
           (name) => [`${name}/package.json`, `${name}/LICENSE`],
         ),
diff --git a/packages/desktop/electron-builder.config.ts b/packages/desktop/electron-builder.config.ts
index 6830c8a9c18..3188999bacc 100644
--- a/packages/desktop/electron-builder.config.ts
+++ b/packages/desktop/electron-builder.config.ts
@@ -77,11 +77,14 @@ const getBase = (appId: string): Configuration => ({
     // Log export imports Zip.js as ESM. Keep index.js and lib, including its inline worker.
     "!**/node_modules/@zip.js/zip.js/dist{,/**/*}",
     "!**/node_modules/@zip.js/zip.js/{index.cjs,index.min.js,index-fflate.js,deno.json,eslint.config.mjs}",
-    // These packages execute compiled JavaScript, not their sources or source maps.
-    "!**/node_modules/{electron-updater,builder-util-runtime,lazy-val}/out/**/*.js.map",
+    // Nothing executes type declarations or source maps, and every entry costs startup time: the
+    // main process parses the whole asar header before it runs any JavaScript.
+    "!**/node_modules/**/*.d.{ts,cts,mts}",
+    "!**/node_modules/**/*.d.{ts,cts,mts}.map",
+    "!**/node_modules/**/*.{js,cjs,mjs}.map",
+    // These packages execute compiled JavaScript, not their sources.
     "!**/node_modules/ajv/lib{,/**/*}",
     "!**/node_modules/ajv-formats/src{,/**/*}",
-    "!**/node_modules/{ajv,ajv-formats}/dist/**/*.js.map",
     // Keep js-yaml's CommonJS sources and dist/js-yaml.mjs ESM entry, not browser bundles or its CLI.
     "!**/node_modules/js-yaml/dist/{js-yaml.js,js-yaml.min.js,*.map}",
     "!**/node_modules/js-yaml/bin{,/**/*}",