Document native root dataset layout

README.md

@@ -125,8 +125,8 @@ memberships = load_dataset(
 ```
 
 `revision=` is optional for ordinary use because `main` is the current release.
-For reproducible training, pass the immutable data commit shown below to
-`load_dataset(repo_id, "samples", ..., revision=revision)` or add
+For reproducible training, pass the immutable data commit shown below as
+`revision="5f0920c3f4edbe7b33e774cb9af445aa4a5b10a0"` to `load_dataset`, or add
 `@<revision>` to an `hf://` URL. The manifest run ID remains inside
 `manifest.json` as provenance; it is not part of the Hub path.
 
@@ -140,7 +140,7 @@ dataset membership.
 
 ## Publication verification
 
-Data commit `ROOT_DATA_COMMIT_PENDING` is the immutable revision for this
+Data commit `5f0920c3f4edbe7b33e774cb9af445aa4a5b10a0` is the immutable revision for this
 release. The upload was checked as 3,293 data objects totaling
 41,557,605,070 bytes: 3,292 Parquet shards plus `manifest.json`. Every local
 object size and SHA-256 matched