polyfill-xml
                                This polyfill is deprecated. Use the symfony/polyfill-php72 package instead.
                            
                        How to download and setup polyfill-xml
Open terminal and run command
                                            git clone https://github.com/symfony/polyfill-xml.git
                                        
                                        git clone is used to create a copy or clone of polyfill-xml 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 polyfill-xml https://github.com/symfony/polyfill-xml/archive/master.zip
Or simply clone polyfill-xml with SSH
                                            [email protected]:symfony/polyfill-xml.git                                    
                                    If you have some problems with polyfill-xml
You may open issue on polyfill-xml support forum (system) here: https://github.com/symfony/polyfill-xml/issuesSimilar to polyfill-xml repositories
Here you may see polyfill-xml alternatives and analogs
symfony grav ilios core-js EasyAdminBundle NelmioApiDocBundle SensioFrameworkExtraBundle LexikJWTAuthenticationBundle VichUploaderBundle DoctrineMigrationsBundle framework-bundle LiipImagineBundle FOSElasticaBundle SncRedisBundle KnpMenuBundle twig-bundle swiftmailer-bundle security-bundle web-profiler-bundle NelmioCorsBundle CraueFormFlowBundle SensioGeneratorBundle web-server-bundle LiipFunctionalTestBundle debug-bundle web-publisher panther http-foundation laravel-zero dialog-polyfill