diff --git a/packages/dev/scripts/pezkuwi-dev-migrate-eslint10.mjs b/packages/dev/scripts/pezkuwi-dev-migrate-eslint10.mjs
index 2fd6a77..ab6dbfe 100755
--- a/packages/dev/scripts/pezkuwi-dev-migrate-eslint10.mjs
+++ b/packages/dev/scripts/pezkuwi-dev-migrate-eslint10.mjs
@@ -14,7 +14,9 @@
 //   pezkuwi-dev-migrate-eslint10 --check   # report, change nothing (exit 1 if anything would change)
 //
 // It also rewrites such comments inside string literals, which is how code
-// generators emit them.
+// generators emit them, and the rule keys of the repository's own
+// eslint.config.* ('import/extensions': 'off'). A rule that became several
+// is reported for a hand edit there, and the tool then exits 1.
 
 import stylisticPlugin from '@stylistic/eslint-plugin';
 import { builtinRules } from 'eslint/use-at-your-own-risk';
@@ -96,6 +98,38 @@ const files = execFileSync('git', ['ls-files', '-z', '--', '*.ts', '*.tsx', '*.j
 const check = process.argv.includes('--check');
 let changedFiles = 0;
 let changedComments = 0;
+let changedKeys = 0;
+/** @type {string[]} */
+const manual = [];
+
+// Rule keys in a repository's own eslint config ('import/extensions': 'off'),
+// quoted or not. Only in eslint.config.* files, where such a key is a rule.
+const CONFIG_FILE = /(^|\/)eslint\.config\.[cm]?[jt]s$/;
+const CONFIG_KEY = /(^|[{,\s])(['"]?)([@a-z][\w@/-]*)\2(\s*:)/g;
+
+/**
+ * @param {string} file
+ * @param {string} src
+ * @returns {string}
+ */
+function renameConfigKeys (file, src) {
+  return src.replace(CONFIG_KEY, (/** @type {string} */ all, /** @type {string} */ pre, /** @type {string} */ _quote, /** @type {string} */ name, /** @type {string} */ colon) => {
+    const next = rename(name);
+
+    if (next.length === 1 && next[0] === name) {
+      return all;
+    } else if (next.length !== 1) {
+      // one rule became several: the value has to be repeated for each, by hand
+      manual.push(`${file}: '${name}' is now ${next.join(', ')}`);
+
+      return all;
+    }
+
+    changedKeys++;
+
+    return `${pre}'${next[0]}'${colon}`;
+  });
+}
 
 for (const file of files) {
   const src = fs.readFileSync(file, 'utf-8');
@@ -116,19 +150,27 @@ for (const file of files) {
     return `${kind}${gap}${next.join(', ')}${tail}`;
   });
 
-  if (out !== src) {
+  const outKeys = CONFIG_FILE.test(file)
+    ? renameConfigKeys(file, out)
+    : out;
+
+  if (outKeys !== src) {
     changedFiles++;
 
     if (check) {
       console.log(`would change: ${file}`);
     } else {
-      fs.writeFileSync(file, out);
+      fs.writeFileSync(file, outKeys);
     }
   }
 }
 
-console.log(`${check ? 'would rewrite' : 'rewrote'} ${changedComments} directive(s) in ${changedFiles} file(s)`);
+for (const line of manual) {
+  console.log(`by hand: ${line}`);
+}
 
-if (check && changedFiles) {
+console.log(`${check ? 'would rewrite' : 'rewrote'} ${changedComments} directive(s) and ${changedKeys} config key(s) in ${changedFiles} file(s)`);
+
+if ((check && changedFiles) || manual.length) {
   process.exit(1);
 }
diff --git a/packages/dev/src/migrateEslint10.spec.ts b/packages/dev/src/migrateEslint10.spec.ts
index e412400..ea42ab5 100644
--- a/packages/dev/src/migrateEslint10.spec.ts
+++ b/packages/dev/src/migrateEslint10.spec.ts
@@ -38,14 +38,40 @@ const header = '/* eslint-disable @stylistic/quotes */';
 // eslint-disable-next-line @typescript-eslint/no-explicit-any
 `;
 
-function inRepo (content: string, args: string[] = []): { out: string; code: number; file: string } {
+const CONFIG_BEFORE = `export default [
+  {
+    files: ['**/*.ts'],
+    rules: {
+      'deprecation/deprecation': 'off',
+      "import/extensions": 'off',
+      indent: 'off',
+      'no-console': 'error'
+    }
+  }
+];
+`;
+
+const CONFIG_AFTER = `export default [
+  {
+    files: ['**/*.ts'],
+    rules: {
+      '@typescript-eslint/no-deprecated': 'off',
+      'import-x/extensions': 'off',
+      '@stylistic/indent': 'off',
+      'no-console': 'error'
+    }
+  }
+];
+`;
+
+function inRepo (content: string, args: string[] = [], name = 'sample.ts'): { out: string; code: number; file: string } {
   const dir = fs.mkdtempSync(path.join(os.tmpdir(), 'migrate-eslint10-'));
-  const file = path.join(dir, 'sample.ts');
+  const file = path.join(dir, name);
 
   try {
     fs.writeFileSync(file, content);
     execFileSync('git', ['init', '-q'], { cwd: dir });
-    execFileSync('git', ['add', 'sample.ts'], { cwd: dir });
+    execFileSync('git', ['add', name], { cwd: dir });
 
     let code = 0;
     let out = '';
@@ -68,14 +94,31 @@ describe('pezkuwi-dev-migrate-eslint10', (): void => {
     const { file, out } = inRepo(BEFORE);
 
     expect(file).toEqual(AFTER);
-    expect(out.includes('rewrote 8 directive(s) in 1 file(s)')).toEqual(true);
+    expect(out.includes('rewrote 8 directive(s) and 0 config key(s) in 1 file(s)')).toEqual(true);
   });
 
   it('leaves current rule names and bare disables alone', (): void => {
     const { file, out } = inRepo(AFTER);
 
     expect(file).toEqual(AFTER);
-    expect(out.includes('rewrote 0 directive(s) in 0 file(s)')).toEqual(true);
+    expect(out.includes('rewrote 0 directive(s) and 0 config key(s) in 0 file(s)')).toEqual(true);
+  });
+
+  it('renames rule keys in eslint.config.*, and only rule keys', (): void => {
+    const { code, file, out } = inRepo(CONFIG_BEFORE, [], 'eslint.config.js');
+
+    expect(file).toEqual(CONFIG_AFTER);
+    expect(code).toEqual(0);
+    expect(out.includes('rewrote 0 directive(s) and 3 config key(s) in 1 file(s)')).toEqual(true);
+  });
+
+  it('leaves a rule that became several to a hand edit, and exits 1', (): void => {
+    const config = "export default [{ rules: { '@typescript-eslint/ban-types': 'off' } }];\n";
+    const { code, file, out } = inRepo(config, [], 'eslint.config.mjs');
+
+    expect(file).toEqual(config);
+    expect(code).toEqual(1);
+    expect(out.includes("by hand: eslint.config.mjs: '@typescript-eslint/ban-types' is now")).toEqual(true);
   });
 
   it('--check reports and changes nothing, exiting 1 when there is work', (): void => {