Crono is a GTD "like" application, made both for real life usage (mine ;) ). It is also a good example on how a Pharo + Spec + Gtk3 application can be made.
You can do something like this:
I still do not have time to do a real bundle and auto-install everything needed, but here is a list of pre-requisittes:
You need: Gtk3 and ejdb2.
use your distro package manager to install libejdb2, gtk3 should be pre-installed
you need to have homebrew installed and execute:
$ brew install gtk3
$ brew install adwaita-icon-theme
$ brew install ejdbTBD
You need the latest Pharo 9 and VM-headless. You can get them with your Pharo launcher, or executing :
$ wget -O- https://get.pharo.org/64/90+vmHeadlessLatest | bash Metacello new
repository: 'github://estebanlm/crono';
baseline: 'Crono';
load. Enjoy :)