Most of ostree is licensed under the LGPLv2+.  This in particular includes
the (presently internal) shared library.

A few bits of code in the tests or the gnomeos/ directory are under
the GPLv2+.  There may also be other licenses such as MIT.

All nontrivial files should have a copyright header comment; if not,
please file a bug at http://bugzilla.gnome.org/.