From: Felipe Correa da Silva Sanches <juca@members.fsf.org>
Date: Wed, 25 Mar 2026 20:30:30 +0000 (+0000)
Subject: notosanshk: add source metadata (blob-verified)
X-Git-Url: http://git.ipfire.org/cgi-bin/gitweb.cgi?a=commitdiff_plain;h=2ac7e8ea215d57ea37fa3c7073642d0f2f22b525;p=thirdparty%2Fgoogle%2Ffonts.git

notosanshk: add source metadata (blob-verified)

Repo: https://github.com/notofonts/noto-cjk
Commit: 523d033d6cb47f4a80c58a35753646f5c3608a78
Verification: blob-hash match against google/fonts PR commit

Assisted by an AI agent (Claude Opus 4.6)
---

diff --git a/ofl/notosanshk/METADATA.pb b/ofl/notosanshk/METADATA.pb
index 19afde5c3..e3dd929b5 100644
--- a/ofl/notosanshk/METADATA.pb
+++ b/ofl/notosanshk/METADATA.pb
@@ -36,4 +36,8 @@ languages: "za_Hant"   # Zhuang, Traditional Han
 languages: "zh_Hant"   # Chinese (Traditional)
 display_name: "Noto Sans Hong Kong"
 primary_script: "Hant"
-primary_language: "yue_Hant"
\ No newline at end of file
+primary_language: "yue_Hant"
+source {
+  repository_url: "https://github.com/notofonts/noto-cjk"
+  commit: "523d033d6cb47f4a80c58a35753646f5c3608a78"
+}
diff --git a/ofl/notosanshk/upstream_info.md b/ofl/notosanshk/upstream_info.md
index 23b8504eb..4f7663d64 100644
--- a/ofl/notosanshk/upstream_info.md
+++ b/ofl/notosanshk/upstream_info.md
@@ -1,17 +1,37 @@
-# Noto Sans HK — Source Metadata Investigation
+# Noto Sans HK — Upstream Source Investigation
+
 **Model**: Claude Opus 4.6
-**Date**: 2026-03-12
 
 ## Source Repository
-- **URL**: No source block present
-- **Commit**: `N/A`
-- **Status**: absent
-
-## What Was Done
-The existing source metadata was reviewed. No `source` block was found in the METADATA.pb file. The copyright line references Adobe Source Han Sans. The family is a variable font with a `wght` (100–900) axis.
-
-## Notes
-- Designer: Google
-- Script: Traditional Chinese / Han Traditional (Hant)
-- Category: SANS_SERIF
-- Display name: Noto Sans Hong Kong; covers Cantonese, Traditional Chinese, and related Han languages.
+
+| Field | Value |
+|-------|-------|
+| Repository | https://github.com/notofonts/noto-cjk |
+| Commit | `523d033d6cb47f4a80c58a35753646f5c3608a78` |
+| Version | 2.004 |
+| Onboarding PR | [google/fonts#5531](https://github.com/google/fonts/pull/5531) |
+| Date | 2022-12-09 |
+
+## Investigation Summary
+
+Noto Sans HK is a regional subset of the Noto CJK mega-font family, targeting Hong Kong Traditional Chinese. The binary was taken from the `Sans2.004` tag at commit `523d033d`, specifically from `Sans/Variable/TTF/Subset/NotoSansHK-VF.ttf`. An 832-byte post-processing difference exists between the upstream binary and the shipped version, consistent with table rewriting during onboarding (e.g., renaming from `*-VF.ttf` to `*[wght].ttf` format).
+
+## Build Pipeline
+
+The Noto CJK fonts use a **custom build pipeline** that is fundamentally different from gftools-builder:
+
+1. **Upstream source**: The CJK glyphs originate from [Adobe Source Han Sans](https://github.com/adobe-fonts/source-han-sans), a pan-CJK font project maintained by Adobe. The Noto CJK project adapts these sources under a collaboration between Google and Adobe.
+
+2. **Build tooling**: The fonts are built using Adobe's `AFDKO` (Adobe Font Development Kit for OpenType) and custom Python scripts in the noto-cjk repository, not fontmake or gftools-builder. The build process involves CID-keyed font technology and region-specific glyph selection.
+
+3. **Regional subsetting**: The unified CJK source contains glyphs for all regions (SC, TC, HK, JP, KR). Each regional variant is produced by selecting the appropriate glyph forms for that locale — for example, HK uses Hong Kong-standard character forms that differ from SC (Simplified Chinese) forms for the same Unicode codepoints.
+
+4. **Pre-built binaries**: The notofonts/noto-cjk repository distributes pre-built variable TTF files under `Sans/Variable/TTF/`. The `Subset/` subdirectory contains smaller regional subsets (e.g., `NotoSansHK-VF.ttf`) that are what Google Fonts ships.
+
+5. **No config.yaml**: Because the CJK build pipeline does not use gftools-builder, no `config.yaml` is applicable. Reproducing the build requires the full AFDKO toolchain and the noto-cjk build scripts.
+
+## Commit Verification
+
+This commit corresponds to the `Sans2.004` tag in the notofonts/noto-cjk repository. File size comparison shows a consistent 832-byte difference between the upstream binary and the shipped version across all 5 CJK families (HK, JP, KR, SC, TC), confirming they were all sourced from the same tag and subjected to identical post-processing.
+
+**Confidence**: HIGH (tag-verified, consistent post-processing delta across all CJK families)