How to download and setup mm3d
Open terminal and run command
                                            git clone https://github.com/clover-moe/mm3d.git
                                        
                                        git clone is used to create a copy or clone of mm3d 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 mm3d https://github.com/clover-moe/mm3d/archive/master.zip
Or simply clone mm3d with SSH
                                            [email protected]:clover-moe/mm3d.git                                    
                                    If you have some problems with mm3d
You may open issue on mm3d support forum (system) here: https://github.com/clover-moe/mm3d/issuesSimilar to mm3d repositories
Here you may see mm3d alternatives and analogs
openage tiled liteide qt qutebrowser MuseScore mapbox-gl-native qTox Clementine antimony flameshot gqrx mixxx appleseed pywebview toggldesktop edb-debugger openauto CuteMarkEd LibreCAD qgroundcontrol otter-browser feedback QDarkStyleSheet stellarium hotspot GoldenCheetah SlicerGitSVNArchive qtbase nitroshare-desktop