Tags give the ability to mark specific points in history as being important
llvm-toolchain-7 Debian release 1:7~+rc3-5
llvm-toolchain-6.0 Debian release 1:6.0.1-9
llvm-toolchain-7 Debian release 1:7~+rc3-4
llvm-toolchain-6.0 Debian release 1:6.0.1-5exp1