Yes it works for s6. You have to install original ROM 7.0 ( you can do it via Samsung Smart Switch ), install TWRP, and install this custom ROM (follow instructions given by author in first post)
3. I want to change the ''Icon Frames'' option in the display options, because I don not like the frames, but the option is grey out and can not be changed. Is this a bug or how can I change it?
You have to change to Original Theme, turn of...