Looks like (unless I've missed a shorter route) with the master docs, to access the API changes you need to click on "Documentation" (top menu), "API Overview", find the small, inconspicuous "See also the API Changes" link (and possibly then again the small "Old API changes" link). (and I only figured that out because I grepped the source...)

It doesn't have to be toplevel, but this seems a bit too well hidden to me.