Apparently we're supposed to use replace for this, not provide

composer.json

@@ -57,7 +57,7 @@
       "phpstan/phpstan-strict-rules": "^2.0.0",
       "phpunit/phpunit": "^10.5.24"
    },
-   "provide": {
+   "replace": {
       "symfony/polyfill-ctype": "*",
       "symfony/polyfill-mbstring": "*"
    },

composer.lock

@@ -4,7 +4,7 @@
         "Read more about it at https://getcomposer.org/doc/01-basic-usage.md#installing-dependencies",
         "This file is @generated automatically"
     ],
-    "content-hash": "d8fa42f33a3bcb26014e6f862366dbd6",
+    "content-hash": "ceb98091ac3f61f1a4b87708c48dc75a",
     "packages": [
         {
             "name": "adhocore/json-comment",