Steps to reproduce

Make sure to have a non-english language set

1. Login
2. Check lang attribute on html element in dev console

Expected behaviour

attribute should be set to same language as the page is displayed

Actual behaviour

Attribute is initially (= after login) set to en although the visible language is a different one.

AFAIK this should be set correctly for accessibility reasons.

https://ocis.ocis-wopi.latest.owncloud.works/