OpenAI 7/13 gpt-oss refresh: open-weight Apache-2.0 + OpenAI usage-policy addendum

OpenAI on 2026-07-13 publishes a refresh of the gpt-oss open-weight line — 120B MoE and 20B dense variants with new post-training snapshots. Self-reported benchmark headlines include MMLU-Pro 84.6, GPQA-Diamond 76.2, SWE-Bench Verified 68.3, BFCL v3 65.4, Terminal-Bench 2.1 76.8. License remains Apache-2.0 with the OpenAI usage-policy addendum.