Easiest: the one-line installer picks the right format by itself (README).
The feed is signed. Install the public key once, then add the feed:
wget -O /etc/apk/keys/vpnpool-apk.pem https://roman-png.github.io/VPNpool/apk/vpnpool-apk.pem echo "https://roman-png.github.io/VPNpool/apk/packages.adb" >> /etc/apk/repositories.d/customfeeds.list apk update apk add luci-app-vpnpool luci-i18n-vpnpool-ru
The feed is signed (usign, fingerprint 807479500e0ce219). Install the public key once, then add the feed:
wget -O /etc/opkg/keys/807479500e0ce219 https://roman-png.github.io/VPNpool/vpnpool-feed.pub echo "src/gz vpnpool https://roman-png.github.io/VPNpool" >> /etc/opkg/customfeeds.conf opkg update opkg install luci-app-vpnpool luci-i18n-vpnpool-ru