Package signing is the act of an open source package (repo, binary, recipe, etc.) being cryptographically signed with a private key so that downstream users can verify the package with a public key. 2FA adds a layer of security by requiring two sources of authentication from maintainers when publishing packages. This helps open source communities avoid supply-chain attacks by protecting packages from their author to their repository. Package signing offers a way to say I trust this maintainer and I am guaranteed that this code was uploaded by them.”]
Source: https://blog.tidelift.com/the-state-of-package-signing-across-package-managers