Accompanying Files
Observation Details
Focusing one of the tabs of "So aktivieren Sie Datenroaming im Ausland" with the screen reader (macOS VoiceOver) will automatically switch to focused tab.
If a screen reader user wants to access the content of the first tab, but pauses moving the focus on the second tab, they won't be able to reach the content of the first tab. As the change is solely visual and not announced to the user, the user might not even know the change, assuming the default functionality of a tab component, ending up on the wrong tab.
Remediation Notes
Tabs can be created in a variety of ways in HTML, thus a general "fix" cannot be defined.
Ensure, the tabs activate on SPACE / ENTER (and screen reader equivalent) rather than activate on focus alone.
Resources to check for Tabs / Tab Groups: