[Libreoffice] License statement: Canonical

[Bjoern Michaelsen]

Hi all,

for reference:

All contributions past and present made to LibreOffice from Canonical
are available under the terms the MPL / LGPLv3+.
Until further notice, future contributions made to LibreOffice from Canonical
are available under the terms the MPL / LGPLv3+.

Best,

Bjoern