https://www.thunderbird.net/en-US/thunderbird/115.12.0/releasenotes/ 未更新
追記
うわ! URL 変わってやんの
https://www-stage.thunderbird.net/en-US/thunderbird/115.12.0/releasenotes/
https://www.mozilla.org/en-US/security/known-vulnerabilities/thunderbird/ 未更新
Security Vulnerabilities fixed in Firefox ESR 115.12 - Mozilla Foundation Security Advisory 2024-28
追記終わり