docs: clarify original source datasets

README.md

@@ -37,12 +37,15 @@ The extraction pipeline draws from pinned snapshots of the following Lean source
 Rows identify their origin in `source_dataset`, `source_url`, `repo_commit`, and
 toolchain columns.
 
-| Source | Role in the corpus |
-|---|---|
-| NuminaMath-CoT | Lean formalizations from the Numina mathematical reasoning corpus. This is the source of the initial uploaded seed. |
-| DeepSeek-Prover | Lean proof data used to broaden theorem and tactic coverage. |
-| Goedel Lean Workbook | Lean workbook proofs, retained as a separately attributable source. |
-| Mathlib | The pinned Mathlib snapshot supplies the theorem-proving environment and contributes directly extracted Mathlib theorems. |
+The extraction uses immutable source revisions: Numina seed `1c12b9b8d6425f3c531c70601b1e70ccb5bc1e6a`, DeepSeek-Prover `1ee889f608fb12ba3596757ee91a60acd663ea81`, Goedel Lean Workbook `b731852af8d8ab11498fda27bce9020738c01c59`, Mathlib `29dcec074de168ac2bf835a77ef68bbe069194c5`, and OProver/OProofs `3bae0c06157639c0a673679635c669d19c99e906`. The Numina seed is retained in this repository as a frozen source snapshot so the packaged rows remain reproducible.
+
+| Source | Pinned original source | Role in the corpus |
+|---|---|---|
+| NuminaMath-CoT | `HyperCactus0/LeanTransitionCorpus` (`sources/numina/frozen-train-cddeac3b98ad642b.parquet`) | Lean formalizations from the Numina mathematical reasoning corpus. This is the source of the initial uploaded seed. |
+| DeepSeek-Prover | `deepseek-ai/DeepSeek-Prover-V1` | Lean proof data used to broaden theorem and tactic coverage. |
+| Goedel Lean Workbook | `Goedel-LM/Lean-workbook` | Lean workbook proofs, retained as a separately attributable source. |
+| Mathlib | `leanprover-community/mathlib4` | The pinned Mathlib snapshot supplies the theorem-proving environment and contributes directly extracted Mathlib theorems. |
+| OProver/OProofs | `OProver/OProofs` | A large corpus of complete Lean proofs used as an additional source. OProofs theorems are checked against the existing theorem-fingerprint index before publication so proofs already represented in this corpus are not added again. |
 
 ## How the data is produced