Wherever there is code a changelog should be in place. NOT for things such as layouts, styles etc. Thats simply ridiculous unless VERY brief.

For example "Added 16 CSS classes" is fine. Dont need define each one and what they do. Added "3 column Layout" fine.

Fixed this/that in code. Fine.

In other words, a brief synopsis of updates. Especially given that the TMT is working to get away from getting function per se away from themes.