--- /dev/null
+# ZCOOL KuaiLe — Upstream Source Investigation
+
+**Model**: Claude Opus 4.6
+**Date**: 2026-03-12
+
+## Summary
+
+The upstream repository for ZCOOL KuaiLe was identified as [https://github.com/googlefonts/zcool-kuaile](https://github.com/googlefonts/zcool-kuaile), which was already recorded in `METADATA.pb`. The source block was missing a `commit` field pointing to a specific upstream revision.
+
+## Investigation
+
+The repository at `googlefonts/zcool-kuaile` was queried via the GitHub API to retrieve the latest commit on the default (`main`) branch.
+
+The latest commit on `main` was identified as `577cd45e035fa0cd27f74579de6ff47db62fde8c`, authored on 2026-01-30, with message: "Update OFL.txt".
+
+## Result
+
+The `commit` field was added to the `source` block in `METADATA.pb`:
+
+```
+Repo: https://github.com/googlefonts/zcool-kuaile
+Commit: 577cd45e035fa0cd27f74579de6ff47db62fde8c
+Branch: main (default)
+Status: commit hash added
+Confidence: high (verified via GitHub API)
+```