139.0.7258.67 Jun 2026

The numbers strongly suggest a Windows Version and Build number, though the formatting is slightly distorted:

It is not intended for daily use by most people. However, for web developers and browser enthusiasts, it offers a preview of web platform features coming to stable Chrome roughly 12–18 weeks after this build’s creation. If you encounter this version in a user agent string or error report, it indicates someone is running a very early, experimental browser. 139.0.7258.67