uri of the package that contains the source of this extension this is ignored if the release type is bundle for php script releases for extension source releases for compiled extension source releases for bundling several releases together in one release tells the installer not to install the default dependency group absolute required dependencies all other optional dependency groups simple optional dependencies version string regex name of the package that contains the source of this extension (can be the same if the source and binaries are in the same package) if a package can provide one or more compatible extensions (dblib/sybase/mssql for instance)