ar71xx is deprecated and has been marked as source only in June 2019. The replacement target for the same hardware is DTS based ath79.
ath79 is the successor of ar71xx. It's modernization under the hood, with the main goal to bring the code into a form that is acceptable for Linux upstream, so that all (most) of the whole ar71xx supported devices can be handled by an upstream, unpatched Linux kernel.