This is a homebrew tap for the Library for Efficient Modeling and Optimization in Networks, which isn't part of homebrew-core (there's another lemon which is a parser generator).
Useful for installing OpenROAD, where the dependencies would become a one-liner:
brew install bison boost cmake The-OpenROAD-Project/lemon-graph/lemon-graph eigen flex git libomp ninja pyqt5 python spdlog swig tcl-tk zlib
brew install The-OpenROAD-Project/lemon-graph/lemon-graph
2-clause BSD license. See 'License'.
These formulas are derived from and are enabled by work of the Homebrew team, who we thank dearly.