That’s very sad 
By the way, it’s available from https://formulae.brew.sh/formula/gkrellm so I was definitely wrong in Trying out Aurora - #37 by lorebett
You also get GUI applications from Homebrew (when available).
However, also in this case, that formula drags in lots of dependencies, including bzip2 that’s already installed in the system.
Those dependencies installed via brew will have the precedence over the ones installed as packages… I’m not sure this is a good thing… 