Datamining is done through comparing the javascript files served to the Canary Client which have different hashes per build change.
Keep in mind that a lot of build changes feature variable renaming, new tabs, newlines, etc.. which usually don't change anything on the user-side. So please take these build notes with a grain of salt.
Important: Every commit (that has some actual noteworthy changes) will have a comment tied to it with a small summary of what's changed. Wiki pages will henceforth not be made anymore.
Legacy: In case a build change is too big to have a diff displayed, I usually try to summarize the changes down at the wiki which can be found here.