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+# PR merge trailer fixture
+
+Poster-authored seed for Arm A and Arm B provider read-back.
+
+Arm A expected generated message-field trailer:
+- `Co-authored-by: be-coder-07 <be-coder-07@fleet.mosaicstack.dev>`
+
+Arm B branch-message trailer:
+- `Co-authored-by: be-coder-06 <be-coder-06@fleet.mosaicstack.dev>`
+
+Absence controls (must not appear in the landed squash object):
+- `Co-authored-by: absent-arm-a <absent-arm-a@example.invalid>`
+- `Co-authored-by: absent-arm-b <absent-arm-b@example.invalid>`
+
+Foreign-authored branch change for linked-author generation.