PHPDoc (of the public API) says that this method returns string but it also returns null, which is not allowed in some method calls. This fixes that behaviour and returns an empty string and fixes all code paths that explicitly checked for null to be still compliant.
Found while enabling the strict_typing for lib/private for the PHP7+ migration.
Signed-off-by: Morris Jobke <hey@morrisjobke.de>
This is not intended anymore, since it falls back to force english
when the header is not set. Also 0228bc6e66
makes clear that the order should be:
1. User setting
2. Accept language
3. Admin default
This is the case since the commit from above, unless via OCS and DAV.
Both forced to accept-language falling back to english.
By removing the force, it now also matches the w3 priority list:
https://www.w3.org/International/questions/qa-lang-priorities
Signed-off-by: Joas Schilling <coding@schilljs.com>
