The repository is part of the Compiler Explorer project. It builds the docker images used to build the various clang compilers used on the site.
This assumes you have set up your user account to be able to run
docker without being root;
if you haven't done so, you'll need to prefix these commands with sudo.
docker build --build-arg image=22.04 -t clangbuilder .docker run clangbuilder ./build.sh trunk
docker run -t -i clangbuilder bash./build.sh trunk