Consider the following command used to clean up the debian archive keyring:
gpg --homedir $(pwd) --quiet --no-keyring --import-options import-export --import /usr/share/keyrings/debian-archive-keyring.gpg > /dev/null
it produces the following noise to stderr:
key 6FB2A1C265FFB764: 3 signatures not checked due to missing keys key 8B48AD6246925553: 6 signatures not checked due to missing keys key CBF8D6FD518E17E1: 2 signatures not checked due to missing keys key 7638D0442B90D010: 4 signatures not checked due to missing keys key 9D6D8F6BC857C906: 4 signatures not checked due to missing keys key EF0F382A1A7B6500: 2 signatures not checked due to missing keys key E0B11894F66AEC98: 5 signatures not checked due to missing keys key EDA0D2388AE22BA9: 5 signatures not checked due to missing keys