I'm going to close this since I presume it is just a misunderstanding. Specifically a footer does not exist on the follow web pages: Conpherence, Workboards. And on mobile we don't have a footer: Conpherence, Workboards, AppSwitcher. These are the only exceptions I can think of off the top of my head. Footers should display in all other cases (web and mobile).

Phabricator is not typically installed publicly (only a handful of installs have) so extending footer to cover "full-screen UI" cases is would be low priority. Mostly we'd need to better understand what exactly installs that need this legally actually need it for and why. If you have immediate need, we'd recommend forking or local patches until we'd be able to find an alternative.

As is sometimes the case with legal issues, I think this request is based on a misunderstanding of the law. The German "Telemedia Act" establishing this requirement ("Telemediengesetz") does not seem to require the link to appear on every page.

This seems to be the actual legal text of the section which establishes the impressum requirement:

http://www.gesetze-im-internet.de/tmg/__5.html

This answer on StackOverflow is somewhat helpful in navigating it:

https://german.stackexchange.com/questions/9796/kontakt-vs-impressum

The actual language is:

(German) Diensteanbieter haben für geschäftsmäßige, in der Regel gegen Entgelt angebotene Telemedien folgende Informationen leicht erkennbar, unmittelbar erreichbar und ständig verfügbar zu halten:
(Google Translate to English) Service providers must have the following information easily accessible, readily accessible and constantly available for commercial, usually paid telemedia:

...and:

(German) § 5 Absatz 1 TMG gibt vor, dass die Angaben leicht erkennbar, unmittelbar erreichbar und ständig verfügbar gehalten werden müssen.
(Google Translate) § 5 paragraph 1 TMG stipulates that the information must be easily recognizable, directly accessible and constantly available.

The StackOverflow answer cites another source to explain this requirement, although I'm not sure where this came from (it's not part of the legal text):

Unmittelbar erreichbar sind Angaben, die ohne wesentliche Zwischenschritte aufgerufen werden können. Nach der Rechtsprechung des BGH kann als gesichert gelten, dass das Erreichen einer Internetseite über zwei Links in der Regel kein langes Suchen erfordert und als unmittelbar gilt.
Immediately accessible are data which can be called without substantial intermediate steps. According to the jurisprudence of the BGH, it can be assured that reaching a website via two links usually does not require a long search and is considered immediate.

Broadly, the intent of this law appears to be protect consumers.

I think Phabricator can already be reasonably configured to satisfy these requirements:

• Phabricator is generally not consumer-facing, so neither the German government nor any individual consumer is likely to have an interest in attempting to enforce impressum requirements against a Phabricator install.
• Phabricator is generally not "commercial/paid telemedia".
• An "Impressum" link in the footer or on the home page seems to satisfy the plain meaning of "easily/immediately/directly recognizable/accessible/available", particularly under the clarifying language ("without substantial intermediate steps", "via two links").

If you are specifically concerned that the mobile home screen does not have an "Impressum" link because it doesn't show the footer, you can add an explicit "Impressum" link in recent versions of Phabricator.