Your requirements could not be resolved to an installable set of packages. Problem 1 - biurad/monorepo is present at version dev-master and cannot be modified by Composer - biurad/git-scm[dev-master, 2.x-dev] cannot be installed as that would require removing biurad/monorepo[dev-master]. They both replace symfony/polyfill-php80 and thus cannot coexist. - Root composer.json requires biurad/git-scm dev-master -> satisfiable by biurad/git-scm[dev-master].