The repository is part of the Compiler Explorer project. It builds the docker images used to build some of the more...esoteric...tools used on the site.
For example, it builds the 6502 compiler.
Note: make sure you chmod +x build/build-yourcompiler.sh
first
sudo docker build -t miscbuilder .
sudo docker run miscbuilder ./build-yourcompiler.sh trunk
sudo docker run -t -i miscbuilder bash
./build-yourcompiler.sh trunk