How to download and setup klayout
Open terminal and run command
                                            git clone https://github.com/KLayout/klayout.git
                                        
                                        git clone is used to create a copy or clone of klayout repositories.
                                        You pass git clone a repository URL. it supports a few different network protocols and corresponding URL formats.
Also you may download zip file with klayout https://github.com/KLayout/klayout/archive/master.zip
Or simply clone klayout with SSH
                                            [email protected]:KLayout/klayout.git                                    
                                    If you have some problems with klayout
You may open issue on klayout support forum (system) here: https://github.com/KLayout/klayout/issuesSimilar to klayout repositories
Here you may see klayout alternatives and analogs
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