**Claim reviewed.** TestBucks executes user-authored pickup-note markup on the staff Orders route.

**Illustrative verdict: SUPPORTED if these artifacts are observed in an isolated TestBucks extension.** The saved synthetic pickup note produced an image element inside `.orders-panel`, its inert same-origin event handler set `window.__testbucksLabXss` to `1`, and the source renders pickup-note rows through `innerHTML`. These independent artifacts agree.

**Strongest counterargument.** The payload and environment are synthetic. That reproduction would establish the vulnerable behavior only in the tested extension; it does not establish reachability, authentication context, browser coverage, or production impact in another deployment.

**Decision.** Preserve the finding as a severe lab release veto. Repair the rendering boundary, rerun the exact payload plus ordinary pickup notes, and add a negative control that must remain inert. Do not broaden the claim beyond the observed revision and environment.