Copying individual secrets to other keyrings

I improperly deleted a particular secret from a keyring.

By copying an older revision of the keyring file, saved in a file-based backup, to the same directory (`~/.local/share/keyrings), but with an alternative file name, I found the deleted secret needed to be restored.

I wish to copy the secret from the backup keyring to the one currently used, both of which are presently opened by the keyring daemon and visible in seahorse.

However, seahorse offers no obvious means to invoke such a use case. How is it possible to complete the simple objective of copying the secret between keyrings?

Discussed in https://gitlab.gnome.org/GNOME/seahorse/-/issues/112.