Constant ONLY_NETHSM_ADMIN_SYSTEMD_CREDS_NON_ADMIN_PLAINTEXT 

const ONLY_NETHSM_ADMIN_SYSTEMD_CREDS_NON_ADMIN_PLAINTEXT: &[u8] = b"system:\n  iteration: 1\n  admin_secret_handling: systemd-creds\n  non_admin_secret_handling: plaintext\n  mappings:\n    - wireguard_download:\n        ssh_authorized_key: ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOh9BTe81DC6A0YZALsq9dWcyl6xjjqlxWPwlExTFgBt user@host\n        system_user: signstar-wireguard-download\nnethsm:\n  connections:\n    - url: https://localhost:8080/\n      tls_security: Unsafe\n    - url: https://localhost:8081/\n      tls_security: Unsafe\n  mappings:\n    - admin: admin\n    - admin: ns1~admin\n    - backup:\n        backend_user: backup\n        ssh_authorized_key: ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAINrIYA+bfMBThUP5lKbMFEHiytmcCPhpkGrB/85n0mAN user@host\n        system_user: nethsm-backup\n    - certificate_retrieval:\n        system_wide: certificateretrieval\n        namespaced:\n          - ns1~certificateretrieval\n        ssh_authorized_key: ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIDvhXirK3o+KPoMqhLlpfPe1UQOqznnAaTOeNtmZraUv user@host\n        system_user: nethsm-certificate-retrieval\n    - hermetic_metrics:\n        backend_users:\n          metrics_user: hermeticmetrics\n          operator_users:\n            - hermetickeymetrics\n        system_user: nethsm-hermetic-metrics\n    - metrics:\n        backend_users:\n          metrics_user: metrics\n          operator_users:\n            - keymetrics\n        ssh_authorized_key: ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIPkpXKiNhy39A3bZ1u19a5d4sFwYMBkWQyCbzgUfdKBm user@host\n        system_user: nethsm-metrics\n    - signing:\n        backend_user: signing\n        signing_key_id: signing1\n        key_setup:\n          key_type: Curve25519\n          key_mechanisms:\n            - EdDsaSignature\n          signature_type: EdDsa\n          key_context:\n            openpgp:\n              notations:\n                test: value\n              user_ids:\n                - Foobar McFooface <foobar@mcfooface.org>\n              version: \"4\"\n        ssh_authorized_key: ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIOh96uFTnvX6P1ebbLxXFvy6sK7qFqlMHDOuJ0TmuXQQ user@host\n        system_user: nethsm-signing\n        tag: signing1\n    - signing:\n        backend_user: ns1~signing\n        signing_key_id: signing1\n        key_setup:\n          key_type: Curve25519\n          key_mechanisms:\n            - EdDsaSignature\n          signature_type: EdDsa\n          key_context:\n            openpgp:\n              notations:\n                test: value\n              user_ids:\n                - Barfoo McBarface <barfoo@mcbarface.org>\n              version: \"4\"\n        ssh_authorized_key: ssh-ed25519 AAAAC3NzaC1lZDI1NTE5AAAAIJr4wdlEv3ZKkDufEQTZSLOjDLO3DeNN2pqKmp00ufIu user@host\n        system_user: nethsm-ns1-signing\n        tag: signing1\n";

Config with NetHSM backend.

• systemd-creds for administrative secrets
• plaintext for non-administrative secrets