HTTP header says "Content-Language: ar"

Description

When using curl -v on FusionDirectory index or webservice, I get "Content-Language: ar" in the headers regardless of the language set in the configuration. The language use is still the one configured though.

Distribution Name and Version

Debian

FusionDirectory Version

1.3-dev

PHP version used

php7

Origin of php packages

Debian

Steps to Reproduce

1. curl -v http://localhost/fusiondirectory/ > /dev/null

Expected behavior:

Content-Language should match the language used in the webpage or in the worst case not be sent.

Actual behavior: Content-Language contains "ar"