mpg.de

The Max Planck Society — 84 research institutes, Germany's largest research organization. 39 requests, 5 domains. Ruby on Rails. Roboto and Merriweather served locally, including Cyrillic. Usercentrics as the CMP — undeclared. Matomo on MPG's own server — declared, not active in the HAR. Set-Cookie — zero.

Timeline of the leak

+0 ms · homepage

www.mpg.de/de — HTML, Apache, Ruby on Rails. A link preload for Roboto 700 woff2 is set in the response header. CSP: frame-ancestors 'self' https://statistik.mpg.de — discloses the Matomo domain.

+280 ms · fonts

Roboto (300, 300italic, regular, 700 — covering Latin, extended Latin, Greek, and Cyrillic) and Merriweather (regular) — five woff2 files, local. mpg_icons-webfont — MPG's own icon font, local. No Google Fonts.

+283 ms · Usercentrics loader

web.cmp.usercentrics.eu/ui/loader.js and WebSdk.lib (+313 ms) — the CMP loader. Followed by banner settings (oO9e28BlWRtyf2), GdprCmpController (+710 ms), a session pixel (+597 ms).

+465 ms · JS bundles

mpg_base.js, mpg_fouc.js, mpg_amd.js, mpg_amd_bundle.js — all local. KaTeX for rendering mathematical formulas — local.

Declared versus actual

✓ Matomo (statistik.mpg.de) — declared, MPG's own server, pk_id and pk_sess cookies — заявлен

✓ Session cookies — declared as technically necessary (§25(2) TDDDG, Art. 6(1)(f)) — заявлен

+ Usercentrics (web.cmp.usercentrics.eu, v1.api.service.cmp.usercentrics.eu, app.usercentrics.eu, uct.service.usercentrics.eu) — not mentioned — не заявлен

Indicators of GDPR non-compliance

GDPR Art. 13(1)(e)

Usercentrics (web.cmp.usercentrics.eu, v1.api.service.cmp.usercentrics.eu, app.usercentrics.eu, uct.service.usercentrics.eu) — the CMP platform, making 7 requests with settingsId=oO9e28BlWRtyf2 — is not mentioned in the privacy policy. The policy declares Matomo on MPG's own server, but does not describe the consent management platform.

Context

Max-Planck-Gesellschaft is Germany’s largest fundamental research organization, bringing together 84 institutes. Nobel laureates: 39 since its founding. Apache, Ruby on Rails. HAR: 39 requests, 5 domains.

Fonts with Cyrillic — local

MPG uses Roboto in four weights with an extended character set: Latin, extended Latin, Greek, Cyrillic — all woff2 files served locally. Merriweather Regular and MPG’s own icon font, mpg_icons-webfont, are also local. A link-preload for Roboto 700 is set directly in the HTTP response header. No Google Fonts.

CSP discloses Matomo — not active in the HAR

The Content-Security-Policy contains frame-ancestors 'self' https://statistik.mpg.de — the host of MPG’s own Matomo instance. The privacy policy describes Matomo with pk_id and pk_sess cookies, IP anonymization, and storage and processing on MPG’s own servers. There are no requests to statistik.mpg.de in the homepage HAR — Matomo was not activated.

Usercentrics — undeclared

Usercentrics makes 7 requests: loader.js, WebSdk, banner settings, GdprCmpController, a 1px session pixel, TCF configuration, and uct analytics (the last returned status 0 — timeout or blocked). The settingsId oO9e28BlWRtyf2 identifies the configuration. Usercentrics is absent from the privacy policy — neither by its own name, nor as a CMP, nor in a cookies section.

KaTeX — for scientific content

The JS bundles include KaTeX — a library for rendering mathematical formulas in TeX/LaTeX notation. Loaded locally, consistent with the profile of a scientific organization.

Conclusion

www.mpg.de has one violation: Usercentrics as the CMP is not declared in the privacy policy. The technical stack is otherwise clean — no ad networks, no external trackers. Matomo on MPG’s own server is correctly declared and is not active in the HAR.

Evidence

Original (audit)

HAR file: de/mpg-de-2026-05-29.har

SHA-256: ad7bdd208944d530b19e059f659a83aa6b5249e1eac368239ee1337ec1fcb791

Re-check snapshot

Awaiting changes

HAR files are stored on EU infrastructure (Proton Drive). SHA-256 is published for integrity verification.

Ready-to-send complaint letter

Where to file: Federal Commissioner for Data Protection (BfDI) — file a complaint online →

To: Federal Commissioner for Data Protection (BfDI)
From: [Your name], [contact email]

1. Subject of the complaint
I am filing a complaint regarding the processing of my personal data by the website mpg.de.

2. Circumstances
I visited the website mpg.de and found indications that the processing of my personal data does not comply with the GDPR. The technical analysis published on gdpru.eu on 29 May 2026 (open methodology, reproducible measurements) documents the following indications:

1) Usercentrics (web.cmp.usercentrics.eu, v1.api.service.cmp.usercentrics.eu, app.usercentrics.eu, uct.service.usercentrics.eu) — the CMP platform, making 7 requests with settingsId=oO9e28BlWRtyf2 — is not mentioned in the privacy policy. The policy declares Matomo on MPG's own server, but does not describe the consent management platform.

Full technical documentation is published at: https://gdpru.eu/en/audits/de-mpg-de/

3. Provisions violated
GDPR Art. 13(1)(e)

4. Request
I request that you investigate the violations described and apply the measures provided for in Article 58(2) GDPR.

5. Attachments
The full evidence base — the HAR file, its SHA-256 checksum and the quotation from the site's privacy policy documenting the stated contradiction — is published and verifiable at the link in point 2 above.

[Date]                                    [Signature / name]