Reassigned to pipeline-stage-view plugin. The build history on the left is properly respecting the user defined TZ setting, stage-view plugin always uses the TZ of the controller.

mawinter69 you're right. I mean the format.

Just checked again, the build history widget respects the locale setting of the browser, switching to german displays the timestamps in 24h format, using english I get 12h format with AM/PM. The widget also respects the user configured timezone.
Also before the re-design of the widget, it was properly making use of the browser locale and the user defined timezone

The screenshot was made with Chrome and German setting.

TZ is set to:

[Service]
# Add JVM configuration options
Environment="JAVA_OPTS=-Djava.awt.headless=true -Dcom.cloudbees.workflow.rest.external.JobExt.maxRunsPerJob=30 -Duser.timezone=Europe/Berlin"

"-Duser.timezone=Europe/Berlin" This is not setting any locale, this just sets the timezone.

And it seems your browser is not set to german, otherwise it should say "Jetzt bauen" and not "Build now".

There is the https://plugins.jenkins.io/locale/ plugin that can force the locale

mawinter69 I mean TZ.

The Locale Plugin was already installed on my Jenkins.

In Jenkins I see

And my Chrome is set to German:

But why is my Jenkins in english? Wondering.

I saved it again and now it's german.

And after it "switched" to german it looks good.

But why was the saved german ignored?

And if I go back to english ...

mawinter69 why is this closed, when this is different?

You opened this ticket originally because you thought that the build history widget has a problem, but it turned out it hasn't.

I would prefer that a new issue is opened specifically claiming that the stage view plugin is not respecting timezone and locale. 

I was not sure which component has the problem. I'll create a new ticket in a few days. Thx.