What do you mean? how it install emacs? As far as I can see there is no reference to emacs in any of our tap files.

The question is what is actually installed and when.

Ok, got it, I've installed cask before since I thought that's needed, yet not anymore. That one pulls emacs.

Fixed with https://github.com/tigase/beagle-im/commit/8e208b6c0e9c810d0e1d50345d517c5fe5e47dc0 and https://github.com/tigase/homebrew-tigase/commit/4d8382e7fceede684a36a933dde1d01cb398439a. Homebrew changed their syntax. Also see issue #87