i tested it again and can confirm you the dependency on >microcore base norestore< without gui, 3.8.4.
i think you can take the chance provide a multifunctional package unison.tcz that works also without gui.
that it works also on the cli, this package needs the dependency to libpng.tcz and Xlibs.tcz.
i tested it in detail:
i booted microcore base norestore in version 3.8.4.
while loading your unison-gui.tcz on the command line interface some errors about missing modules appear:
module error for libpixbufloader-tiff.so
module error for libpixbufloader-png.so
module error for libpixbufloader-jpeg.so
after starting unison on the command line, the error message of a missing libpng.so.0 is reported,
the loading of libpng.tcz resolves this problem.
after starting again unsion on the command line, the error message of a missing libfreetype.so.6 is reported,
the loading of Xlibs.tcz resolves also this problem
and afterwards unison starts without errors!!!
so i recommend these two dependencies to make this >unison.tcz< universal for gui and cli.
and please load it up in both repositories, 3.x and 4.x, and remind the opinion of bmarkus to call it >unison.tcz<.
the icon in 48x48 makes it even better.