Checked into GIT based on the considerable testing by Andrea as noted below.

Finally, a consideration. Without your patches the RGBA-FLOAT color
model is almost useless with plugins because it allows unclipped
calculations only for Gamma and Blue Banana. With your patches almost
all plugins work in floating point (even Videoscope, without the
"smooth" option); only HistEQ and Histogram Bezier remain excluded. So
I think your patches are an important addition to CinGG. Do you think
it's better to try to make an appimage with your patches so that
others can test them, or can we put them directly into git, since I've
done a lot of testing by now without the slightest problem?

Phyllis, what do you think?

I think the addition is good and hopefully will not cause any unforeseen issues. I did test a little just to see what the results would be.