Provenance Record

Well-structured News piece with clear sectioning (Overview, What We Know, What Is Not in This Edition, What We Don't Know). Appropriate technical depth for the audience; 529 words within the News 400-1200 range.

All 5 source snapshots read from disk and verified. source-0 (InfoWorld, HTTP 200): confirms 17th edition, June 30 approval, and the built-in descriptions. source-1 (tc39/ecma262 releases, 200): verbatim confirms 'TC39 approved this in March 2026; Ecma approved it on June 30th, 2026.', the ES2026 candidate tag of March 31, and ES2025 approval on June 25, 2025. source-2 (tc39 finished-proposals table, 200): confirms exactly seven proposals with a 2026 expected publication year (Upsert, JSON.parse source text access, Iterator Sequencing, Uint8Array to/from Base64, Math.sumPrecise, Error.isError, Array.fromAsync); RegExp.escape marked 2025; and Temporal, Explicit Resource Management, and Joint Iteration all marked 2027. Champions (Harband, Minor, Choi, Gibbons, Ficarra, Gibson) and historical dates (Error.isError 2016-03, Upsert 2019-10 with latest presentation 2026-01, Array.fromAsync 2021-08) all match the table. source-3 (proposal-upsert, 200): getOrInsert/getOrInsertComputed and WeakMap counterparts and the quoted method description verified verbatim. source-4 (proposal-arraybuffer-base64, 200): all six methods and the '{ read, written } pair' quote verified verbatim; the decode-throws claim is an accurate paraphrase.

All substantive facts verify against the snapshots, including the critical checks: exactly seven finished proposals, the 17th-edition number, and the correct exclusion of Temporal/Explicit Resource Management/Joint Iteration as 2027 (not 2026). No proposal is misattributed to the wrong edition.

Accurate, well-sourced, original ES2026 report. The only defect is minor quote imprecision on three InfoWorld phrases, honestly summarizable in a single corrections note. Verdict: APPROVE_WITH_CORRECTIONS.