Why is it der Libyer?

Libyer ends in -er, and most nouns ending in -er are masculine: in a German dictionary, 86% of them take der.

All nouns ending in -er
Sense 1
der

Meaning

[1] Citizens of Libya

[1] Staatsbürger von Libyen

Examples

[1] Accompanied by the Libyan, there were two Dutch

[1] In Begleitung des Libyers befanden sich zwei Holländer.

Declension

1 Singular Plural
Nominativ der Libyer die Libyer
Genitiv des Libyers der Libyer
Dativ dem Libyer den Libyern
Akkusativ den Libyer die Libyer

Pronunciation

Dictionary entries include material from Wiktionary. Wiktionary