Steps to reproduce the issue

1. Install XAMPP
2. Extract Joomla 4 Alpha 5 package in "htdocs"
3. Launch installation
4. When required, choose to "Customize Installation" and try and install a Language pack, i.e. "Italian"

Expected result

A Language pack should be installed

Actual result

Apache crashes with following error in logs:
[Fri Aug 10 12:01:05.081166 2018] [php7:notice] [pid 5172:tid 1236] [client ::1:55518] PHP Notice: Trying to get property '_data' of non-object in C:\xampp\htdocs\joomla4\installation\src\Model\LanguagesModel.php on line 253, referer: http://localhost/joomla4/installation/index.php?view=remove&layout=default

System information (as much as possible)

Additional comments