https://www.archlinuxcn.org/archlinuxcn-keyring-manually-trust-farseerfc-key/

The keyring package archlinuxcn-keyring of the archlinuxcn community repository is signed and verified by the key of farseerfc, which is included in the Arch Linux official keyring. However, the removal of a retired master key from the archlinux-keyring in early December resulted in insufficient trust for farseerfc's key, as calculated by GnuPG's web of trust, leading to the automatic trust of the signature of the archlinuxcn-keyring package no longer being possible.

If you encounter the following error when trying to install the archlinuxcn-keyring package in the new system:

1error: archlinuxcn-keyring: Signature from "Jiachen YANG (Arch Linux Packager Signing Key) " is marginal trust

Please use the following command to trust the key of farseerfc locally. This key has been installed in the system with archlinux-keyring, it just lacks trust.

1sudo pacman-key --lsign-key "farseerfc@archlinux.org"

Afterwards, continue installing archlinuxcn-keyring:

1sudo pacman -S archlinuxcn-keyring