I asked Bassam if it would be completely open source (and not open core like GitLab) in the architecture document [0]. He said it would be completely open source [1].

0. https://docs.google.com/document/d/1whncqdUeU2cATGEJhHvzXWC9...

1. https://www.dropbox.com/s/bypp7unw8802gkr/Screenshot%202018-...