def overrides(self) -> dict[str, Requirement]:
        """A mapping of package name to the requirement for overriding."""
        from pdm.formats.requirements import RequirementParser

        project_overrides: dict[str, str] = {
            normalize_name(k): v
            for k, v in self.repository.environment.project.pyproject.resolution.get("overrides", {}).items()
        }
        requirements: dict[str, Requirement] = {}
        for name, value in project_overrides.items():
            req = get_requirement_from_override(name, value)
            r = parse_requirement(req)
            requirements[r.identify()] = r

        # Read from --override files
        parser = RequirementParser(self.repository.environment.session)
        for override_file in self.repository.environment.project.core.state.overrides:
            parser.parse_file(override_file)
        for r in parser.requirements:
            # There might be duplicates, we only keep the last one
            requirements[r.identify()] = r

        return requirements
A mapping of package name to the requirement for overriding.
src/pdm/resolver/providers.py