berbera

Berbera is the adjective and berbero is the person, which is Esperanto's regular pattern for a people: -o for the human being, -a for everything belonging to them. The full machinery, including the -ujo and -io question for countries, is in countries and peoples.

The name is not theirs, and that is worth saying on the page rather than leaving in a footnote. Arabic barbar is generally traced to Greek barbaros, the Greek word for anybody whose speech sounded like meaningless bar-bar, and it has been applied from outside ever since, by Greeks, Romans, Arabs and Europeans in turn. The people's own name for themselves is Amazigh, plural Imazighen, meaning something close to free people, and it is increasingly what you will meet in print and on the flags.

So use berbero and berbera as the words a general reader will recognise, reach for Amazigh with a gloss when precision matters, and do not reach for maŭro. That one is a medieval European label for Muslims from over there which lumps Berbers, Arabs and Iberian converts together indiscriminately, and it belongs in historical writing about al-Andalus and nowhere else.