Why not build stable channel version?

Here is release schedule of Chromium https://chromiumdash.appspot.com/schedule I noticed you were building very early versions. Is there a particular reason for that? If you need to reduce the number of builds, you can build the last minor version of the stable channel. Taking Windows platform as an example https://chromiumdash.appspot.com/releases?platform=Windows For example, the stable channel is now version 139, and the 138 stable channel has ended, and obviously the last version is 138.0.7204.185. Note：I don't speak English, the above content is the result of Google translation, please forgive me if can't understand it.