Failed to execute git checkout e9de2e0611e43ef7430ddc2c4ebb664dbb73240d -- && git reset --hard e9de2e0611e43ef7430ddc2c4ebb664dbb73240d -- fatal: unable to read tree (e9de2e0611e43ef7430ddc2c4ebb664dbb73240d) It looks like the commit hash is not available in the repository, maybe the commit was removed from the branch? Run "composer update silverstripe/developer-docs" to resolve this.