Dictionary of Medieval Names
from European Sources

Liberto m. Latin libertus 'freedman, ex-slave'.

Some examples from Germany and the Low Countries may in fact belong with Liutbert.

France
Latin
1378 Liberto (dat) hanquetvol1 412
Cite as: S.L. Uckelman. "Liberto". In S.L. Uckelman, ed. The Dictionary of Medieval Names from European Sources, Edition 2016, no. 4. http://dmnes.org/2016/4/name/Liberto.