A Word document can change its XML-save transform without changing its text

Ordinary text diffs cannot explain every consequential WordprocessingML change.
A document can keep every stored text node and its entire Settings XML fixed
while changing the external transform configured for a single-XML save.

Document Change Assurance Benchmark 0.18.0
adds its twenty-ninth deterministic pair:
external.save_through_xslt_target_retargeted.

Both packages preserve their member set, stored w:t values, explicit enabled
setting, transform anchor, relationship ID, and all Settings XML. Only
word/_rels/settings.xml.rels changes, where a synthetic external transform
target is retargeted.

The complete static topology matters

Microsoft documents SaveThroughXslt
as a custom XSL transform used when a document is saved as a single XML file.
UseXsltWhenSaving
controls whether it is applied. The OOXML Document Settings relationship
contract defines the associated transform
relationship as external.

word/settings.xml                         fixed on both sides
  w:useXSLTWhenSaving true               fixed enabled state
  w:saveThroughXslt r:id                 fixed transform anchor

word/_rels/settings.xml.rels             only changed package member
  transform relationship / target         synthetic target retargeted

The fixture models configuration, not execution. It does not include a
transform payload, fetch or parse one, save a document through one, open Word,
or claim emitted XML or client behavior.

A target-free oracle and a real consumer

The public truth names only save_through_xslt_target_changed, an external
binding class, a generic XML-transform relationship category, and the Word
Settings source. It excludes both targets, the relationship ID, relationship
path, and local solution identifiers. URI-like fixture values use the reserved
example.invalid domain.

The optional DocFence 0.28.0
adapter reaches a strict 29/29 score from aggregate evidence:
external_relationships_changed, save_through_xslt_inventory_changed, one
enabled setting, one anchor, one external transform relationship, and no local
solution identifier. It never consumes a target, ID, path, or private
fingerprint.

Hosted CI passed on Python 3.11–3.13 for the main commit and release tag. The
standard python-docx reader opens all 56 .docx fixtures and its OPC reader
opens all 58 packages. Clean wheel/source-distribution installs validate the
bundled corpus, and the public Hugging Face dataset
mirror was byte-verified against the generated tree.

python -m pip install https://github.com/SybilGambleyyu/document-change-benchmark/releases/download/v0.18.0/document_change_benchmark-0.18.0-py3-none-any.whl
dcab validate
dcab docfence-observations --executable docfence --output observations.json
dcab score --observations observations.json --strict

DCAB keeps fixture schema version 1: this is one new static-review fact, not a
transform engine, Word emulator, renderer, or universal policy claim. Read the
canonical release note
for the exact package and privacy contract.