GitCover Symbol GCBoKGitCover Body of Knowledge

ED20 - Government Interface Practice: ELSTER, DE-Mail, eXTra - Mediation by GitCover

Problem

Many government agency interfaces are regulated by law, but in practice barely usable for laypeople:

Core Statement

The GitCover harness mediates between external systems and risk-affine regulations:

  1. ELSTER mediation - LStA, UStA, LSt-Bescheinigung via ELSTER interface; receipt as evidence with sidecar
  2. DE-Mail: Discontinued - migration required - historical DE-Mail messages must be migrated into the repo as EML + SHA-256 + sidecar before discontinuation; archived emails in discontinued systems are no longer accessible - GoBD retention problem
  3. eXTra/euBP export - SV data in eXTra format exportable for DRV audits
  4. Z3 data carrier export - GoBD-compliant Z3 export for FA external audits (git bundle as self-contained archive)
  5. Interface error logging - errors/aborts of external systems are logged as repo events
  6. Regulation binding - every interface transaction is mapped to the risk-affine regulation

Compliance by Design: The harness does not hide the complexity of government interfaces - it documents it. Every transmission, every receipt, every error is recorded in the repo in a traceable manner.

The Government Interface Landscape

%%{init: {'theme':'base','themeVariables':{'primaryColor':'#FBFAF7','primaryTextColor':'#0F1B33','primaryBorderColor':'#6B7280','lineColor':'#6B7280'}}}%% flowchart TD U["Unternehmer E1"] U --> H["GitCover-Harness"] H --> EL["ELSTER"] H --> DM["DE-Mail (eingestellt)"] H --> EX["eXTra/euBP"] H --> Z3["Z3-Datenträger"] EL --> FA["Finanzamt"] DM --> BH["Behörden (diverse)"] EX --> DRV["DRV (SV-Prüfung)"] Z3 --> AP["Finanzamt (Außenprüfung)"] style U fill:#0F1B33,stroke:#0F1B33,color:#FBFAF7 style H fill:#10A987,stroke:#0A7F5C,color:#FBFAF7 style EL fill:#DBEAFE,stroke:#1D4ED8,color:#0F1B33 style DM fill:#FDBA74,stroke:#C2410C,color:#0F1B33 style EX fill:#DBEAFE,stroke:#1D4ED8,color:#0F1B33 style Z3 fill:#DBEAFE,stroke:#1D4ED8,color:#0F1B33 style FA fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style BH fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style DRV fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style AP fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33
Interface Purpose Complexity GitCover mediation
ELSTER LStA, UStA, LSt-Bescheinigung, e-invoice viewer high (certificate, XML, client) Receipt as evidence with sidecar
DE-Mail Secure communication with government agencies discontinued (last provider 31.12.2026) Migration: EML + sidecar into repo; warning
eXTra/euBP SV data for DRV audits high (special format) Export from repo data
Z3 data carrier GoBD-compliant export for FA external audit high (specialized software) git bundle as self-contained archive

ELSTER Mediation

%%{init: {'theme':'base','themeVariables':{'primaryColor':'#FBFAF7','primaryTextColor':'#0F1B33','primaryBorderColor':'#6B7280','lineColor':'#6B7280'}}}%% flowchart TD L["LStA/UStA berechnet"] L --> E["ELSTER-Übermittlung"] E --> Q["ELSTER-Quittung"] Q --> S["Quittung als Beleg mit Sidecar"] S --> R["Repo: LStA-Eintrag mit source_sha256"] R --> V["Vorschriften-Binding: § 41a EStG"] E -->|Fehler| F["Fehler-Logging im Repo"] F --> FR["Repo-Ereignis: ELSTER-Fehler"] style L fill:#0F1B33,stroke:#0F1B33,color:#FBFAF7 style E fill:#DBEAFE,stroke:#1D4ED8,color:#0F1B33 style Q fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style S fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style R fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style V fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style F fill:#FDBA74,stroke:#C2410C,color:#0F1B33 style FR fill:#FDBA74,stroke:#C2410C,color:#0F1B33
Step Action GitCover implementation
LStA calculated Payroll tax registration from payroll accounting JSON artifact in repo (see ED14)
ELSTER transmission Electronically via ELSTER (certificate required) Harness calls ELSTER
Receipt ELSTER confirms transmission Receipt as evidence with sidecar
Repo entry LStA with source_sha256 on receipt tags: ["lsta", "§41a-estg"]
Regulation binding LStA → § 41a EStG vorschrift: "§41a-estg" in the artifact
Error logging ELSTER error is logged Repo event with error description

Regulation binding: Every interface transaction is mapped to the risk-affine regulation - e.g., LStA → § 41a EStG, UStA → § 18 UStG, LSt-Bescheinigung → § 41b EStG. This makes it traceable which regulation was fulfilled by which transmission.

DE-Mail - Discontinued: Migration and Archiving Consequences

DE-Mail is officially discontinued. The project is considered failed. The last provider (FP Digital Business Solutions GmbH) will discontinue the service on 31.12.2026 - after that, DE-Mail is no longer usable and archived emails in these systems are no longer accessible.

Event Date Source
Telekom discontinues De-Mail 31.08.2022 "due to lack of economic viability"
1&1 De-Mail GmbH discontinues 07.02.2025 service no longer reachable
§ 130a ZPO repealed 22.12.2025 DE-Mail as secure transmission channel abolished (BGBl. 2025 I Nr. 349)
Federal administration discontinues July 2024 mandatory use discontinued
Last provider (FP Digital) discontinues 31.12.2026 "That is the end of DE-Mail"
Federal Court of Audit 2021 2021 2011-2020: ~6,000 DE-Mail messages from government agencies, savings ~3,500 EUR, costs >= 6.5 million EUR
CCC criticism 2013 Linus Neumann (30C3): "Bullshit made in Germany - deliberately built insecure"

DE-Mail is history: The last provider (FP Digital Business Solutions GmbH) will discontinue the service on 31.12.2026. The legal recognition as a secure transmission channel (§ 130a Abs. 4 Nr. 1 ZPO) was repealed on 22.12.2025. The federal administration discontinued mandatory use in July 2024. The Federal Court of Audit reported in 2021: 6.5 million EUR in costs for ~3,500 EUR in savings. A "European Business Wallet (EBW)" is planned as a successor.

Consequences of Archived Emails in Discontinued Systems

When a DE-Mail provider discontinues its service, immediate GoBD-relevant retention problems arise:

Problem Consequence GoBD reference
Mailbox no longer accessible Emails can no longer be retrieved § 146 Abs. 5 AO ("available at any time")
Provider-side deletion Data is deleted after shutdown § 147 Abs. 1 AO (6-year retention obligation)
No export possible If the provider does not offer an export function, data is irretrievably lost GoBD Rz. 146 (traceability)
Evidentiary value lost DE-Mail-specific confirmations (send/delivery confirmation) are no longer verifiable Loss of evidence in disputes with government agencies
No forensic evidence preservation A layperson can hardly retrospectively improve the authenticity of old emails forensically - without provider infrastructure, the verification data is missing (signature verification, timestamp server, provider logbooks) Downgrading of evidentiary value to a "mere PDF copy"
Retention period still running Emails from 2024 must be retained until 31.12.2030 - but the system is gone in 2026 GoBD violation due to unavailable retention

Forensic evidence preservation - hardly recoverable: DE-Mail-specific evidence features (qualified electronic signature of the send and delivery confirmation, provider timestamp, integrity hash value) can only be verified within the running provider infrastructure. After shutdown, this verification data is no longer available. A layperson cannot subsequently check an exported EML file for its DE-Mail-specific authenticity - the signature verification fails due to the missing provider certificate, the timestamp server is offline, the provider logbooks have been deleted. The email loses its status as "legally binding DE-Mail communication" and degenerates into a mere PDF copy with greatly reduced evidentiary value. Retrospective forensic evidence preservation by an expert would be theoretically possible, but practically hardly feasible - the required provider infrastructure data no longer exists.

Critical warning - migration before shutdown: Entrepreneurs who still have a DE-Mail mailbox must export all relevant emails as EML files before shutdown and migrate them into the Git repo (EML + SHA-256 + sidecar). After shutdown, an export is no longer possible - the data is irretrievably lost. This is a GoBD violation if the retention period is still running (6 years from the end of the year, § 147 Abs. 1 Nr. 2/3 AO).

GitCover Migration: DE-Mail -> Repo

%%{init: {'theme':'base','themeVariables':{'primaryColor':'#FBFAF7','primaryTextColor':'#0F1B33','primaryBorderColor':'#6B7280','lineColor':'#6B7280'}}}%% flowchart LR D["DE-Mail-Postfach (eingestellt)"] D --> EX["Export vor Abschaltung"] EX --> EML["EML-Dateien"] EML --> SH["SHA-256 pro EML"] SH --> SC["Sidecar .gc.md pro EML"] SC --> R["Repo: sources/korrespondenz/"] R --> OK["GoBD-konform archiviert"] D -->|nach Abschaltung| LOST["Daten unwiederbringlich verloren"] LOST --> V["GoBD-Verstoß"] style D fill:#FDBA74,stroke:#C2410C,color:#0F1B33 style EX fill:#DBEAFE,stroke:#1D4ED8,color:#0F1B33 style EML fill:#DBEAFE,stroke:#1D4ED8,color:#0F1B33 style SH fill:#DBEAFE,stroke:#1D4ED8,color:#0F1B33 style SC fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style R fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style OK fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style LOST fill:#FDBA74,stroke:#C2410C,color:#0F1B33 style V fill:#FDBA74,stroke:#C2410C,color:#0F1B33
Step Action Deadline
Export Export all relevant emails as EML before shutdown (at the latest 31.12.2026)
SHA-256 Calculate hash per EML file during migration
Sidecar .gc.md per EML with classification during migration
Filing EML + sidecar in sources/korrespondenz/ during migration
Verification Check completeness (number of emails) after migration

Practical tip: The migration should be carried out immediately, not only shortly before shutdown. Providers can restrict the service early (e.g., no new registrations, limited export). Anyone who waits risks data loss.

%%{init: {'theme':'base','themeVariables':{'primaryColor':'#FBFAF7','primaryTextColor':'#0F1B33','primaryBorderColor':'#6B7280','lineColor':'#6B7280'}}}%% flowchart LR D["DE-Mail (eingestellt)"] D --> P["Gescheitert: 6,5 Mio EUR Kosten, ~3500 EUR Nutzen"] P --> W["Warnung: DE-Mail nicht nutzen"] W --> A["Alternative: ELSTER-Postfach"] D --> E["Eingehende Behörden-E-Mail (historisch)"] E --> AR["EML archiviert + Sidecar"] AR --> V["Absender-Verifikation (DKIM/SPF)"] style D fill:#FDBA74,stroke:#C2410C,color:#0F1B33 style P fill:#FDBA74,stroke:#C2410C,color:#0F1B33 style W fill:#FDBA74,stroke:#C2410C,color:#0F1B33 style A fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style E fill:#DBEAFE,stroke:#1D4ED8,color:#0F1B33 style AR fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style V fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33
Aspect Problem GitCover solution
Status DE-Mail officially discontinued (last provider 31.12.2026) Warning: do not use; migration required
Cost/benefit 6.5 million EUR costs, ~3,500 EUR savings (Federal Court of Audit) git bundle and ELSTER mailbox are free
Security "deliberately built insecure" (CCC, Linus Neumann 2013) Git + GPG + SHA-256
Legal recognition § 130a ZPO repealed on 22.12.2025 no longer relevant
Archiving archived emails in discontinued systems no longer accessible Migration: EML + SHA-256 + sidecar into repo
Retention period Emails from 2024 must be retained until 2030 - system gone in 2026 GoBD violation for non-migrated data
Successor European Business Wallet (EBW) planned open; GitCover independent

DE-Mail disaster mitigation: The harness warns when DE-Mail is used (if historical mailboxes still exist) and recommends immediate migration of all relevant emails as EML + sidecar into the repo. After shutdown (at the latest 31.12.2026), the data is irretrievably lost - a GoBD violation if the retention period is still running. As an alternative for future communication: ELSTER mailbox for tax topics, regular email + sidecar archiving for correspondence.

eXTra/euBP Export and Z3 Data Carrier

%%{init: {'theme':'base','themeVariables':{'primaryColor':'#FBFAF7','primaryTextColor':'#0F1B33','primaryBorderColor':'#6B7280','lineColor':'#6B7280'}}}%% flowchart TD R["Repo-Daten (JSON, Sidecars)"] R --> EX["eXTra-Export"] R --> Z3["Z3-Export (git bundle)"] EX --> DRV["DRV-Prüfung: SV-Daten"] Z3 --> FA["FA-Außenprüfung: GoBD-Daten"] EX --> F1["Format: eXTra V3.4.0"] Z3 --> F2["Format: git bundle + Manifest"] style R fill:#0F1B33,stroke:#0F1B33,color:#FBFAF7 style EX fill:#DBEAFE,stroke:#1D4ED8,color:#0F1B33 style Z3 fill:#DBEAFE,stroke:#1D4ED8,color:#0F1B33 style DRV fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style FA fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style F1 fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style F2 fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33
Export Purpose Format Recipient
eXTra/euBP SV data for DRV audit eXTra V3.4.0 (XML) DRV
Z3 (git bundle) GoBD data for FA external audit git bundle + manifest + static web (Z3+) FA

Practical example: During a company audit, the DRV requests SV data in eXTra format. The harness exports the relevant payroll and SV data from the repo as eXTra XML. During an external audit, the FA requests GoBD-compliant data (Z3) - the harness generates a git bundle + static web (Z3+, see ED05). Both exports can be generated from the structured repo data (JSON, sidecars) - no manual preparation needed.

Interface Error Logging

%%{init: {'theme':'base','themeVariables':{'primaryColor':'#FBFAF7','primaryTextColor':'#0F1B33','primaryBorderColor':'#6B7280','lineColor':'#6B7280'}}}%% flowchart TD S["Schnittstellen-Aufruf (ELSTER, DE-Mail)"] S --> OK["Erfolg: Quittung + Sidecar"] S --> ERR["Fehler: Abbruch, Timeout, Formatfehler"] ERR --> L["Fehler-Logging im Repo"] L --> E["Repo-Ereignis: Schnittstellen-Fehler"] E --> N["Nachweis: Fehler nicht verschuldet"] style S fill:#0F1B33,stroke:#0F1B33,color:#FBFAF7 style OK fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33 style ERR fill:#FDBA74,stroke:#C2410C,color:#0F1B33 style L fill:#FDBA74,stroke:#C2410C,color:#0F1B33 style E fill:#FDBA74,stroke:#C2410C,color:#0F1B33 style N fill:#D1FAE5,stroke:#0A7F5C,color:#0F1B33
Event Action GitCover implementation
Success Receipt archived Evidence with sidecar, source_sha256 in artifact
Error Error logged Repo event with error description, timestamp, regulation
Proof "error not caused by own fault" Repo event as evidence during audit

Important - shift of liability: If an interface fails (e.g., ELSTER timeout on the 10th of the month), the error logging in the repo documents that the entrepreneur tried to transmit on time. This is evidence in the case of § 152 AO (late filing penalty) - the entrepreneur can argue that the error was not within their sphere.

Risk Leverage

Today (cheap) Tomorrow (audit-proof) Risk reduced
ELSTER receipt as evidence with sidecar Transmission provable Late filing penalty § 152 AO
DE-Mail warning + alternative Suitable channel selected Loss of communication
eXTra export from repo data SV data available for DRV audit GoBD violation during DRV audit
Z3 export as git bundle GoBD data available for FA audit GoBD violation during FA audit
Interface error logging Proof "tried" Shift of liability in case of interface failure
Regulation binding Regulation documented per transmission Contestation of regulation fulfillment

Harness Requirement (Preview)

Derived from ED20:

ID Requirement Priority
FA-12.1 ELSTER mediation: LStA, UStA, LSt-Bescheinigung; receipt as evidence with sidecar MUST
FA-12.2 DE-Mail/De-Mail bridge: EML + SHA-256 + sidecar; sender verification SHOULD
FA-12.3 eXTra/euBP export: SV data in eXTra format for DRV audits SHOULD
FA-12.4 Z3 data carrier export: GoBD-compliant Z3 export (git bundle) SHOULD
FA-12.5 Interface error logging: errors as repo event MUST
FA-12.6 Regulation binding: every transaction mapped to risk-affine regulation SHOULD
FA-12.7 DE-Mail disaster mitigation: warning for unsuitable channels NICE
FA-12.8 Government agency identifier registry MUST

The complete requirements list is in Harness-Anforderungen.md.

Sources

Role Location Purpose
Primary / SSoT git.gitcover.org/GCC Canonical storage (GPG-signed, versioned)
Public OSS Mirror / CDN codeberg.org/gitcover-commons Read-only mirror; FLOSS discovery
Community Hub github.com/gitcover-commons Issues & Discussions; source code reference on Codeberg

Note: This assignment of sources, mirror, and community hub reflects the current state and may change. Please check the respective canonical source on gitcover.org for the current state.