tell me more about the timestamp. Where does that data get derived? I thought that should be in great shape since I set lastmod in my sitemap based on git commi

tell me more about the timestamp. Where does that data get derived? I thought that should be in great shape since I set lastmod in my sitemap based on git commit date https://johnnyreilly.com/2022/11/25/adding-lastmod-to-sitemap-git-commit-date https://johnnyreilly.com/2022/11/25/adding-lastmod-to-sitema...