Does KHR_mesh_quantization allow unnormalised byte/short NORMAL and TANGENT, and is the extension optional? No: NORMAL and TANGENT may only use normalised byte/short, and files using the extension must list it in extensionsRequired.

Problem. C2-B06-D-10 says the extension allows byte/short 'normalized or not' POSITION, NORMAL, TANGENT and TEXCOORD, and does not say the extension is mandatory. Conditions. glTF assets using KHR_mesh_quantization. Method. The README table lets POSITION and TEXCOORD_n use normalised or unnormalised byte/short (POSITION also unsigned); NORMAL and TANGENT are allowed only as normalised byte or short; morph target NORMAL/TANGENT likewise normalised only, with large displacements needing FLOAT. Because the quantised and FLOAT forms cannot coexist, the file must list the extension in extensionsRequired, so viewers lacking it must reject the file. Failure modes. An encoder writing unnormalised int NORMALs, or omitting extensionsRequired, produces non-conformant or unreadable files. Limitations. Table detail was read from the README at commit 7cee0fc; other aspects of C2-B06-D-10 (dequantisation in node transform, inverseBindMatrices, KHR_texture_transform, shared morph transform) were confirmed. Version/date. Registry commit 7cee0fc, extension status Complete, Ratified. Curator qualifications: All cited documentation excerpts located on the live pages by curator GET; no video sources. Correction of earlier record(s) C2-B06-D-10 from a discovery re-fetch on 2026-10-23; the curator re-located the cited excerpts by GET. Limitations: Component-type restrictions for NORMAL/TANGENT are in a table that is not quoted (table cells span markup); the claim rests on reading the table rows, flagged as inference from the table. Classification (b)+(c). Evidence status: statements located in the cited sources by a correlated desk review (Claude); not executed; not independently reviewed.

{
  "citations": [
    {
      "url": "https://raw.githubusercontent.com/KhronosGroup/glTF/7cee0fcddd5730e90d488bfb5aa2e52171483dde/extensions/2.0/Khronos/KHR_mesh_quantization/README.md",
      "note": "Overview; Extending Mesh Attributes"
    }
  ]
}