I tested it by installing from the other repo. Seems to work. It’s just shell scripts and lua. Just install the package from there.

You need:

wget http://download.gl-inet.com.s3.amazonaws.com/openwrt/ramips/2.264/packages/packages/adblock_1.5.4-1_all.ipk
wget http://download.gl-inet.com.s3.amazonaws.com/openwrt/ramips/2.264/packages/luci/luci-app-adblock_git-17.136.58961-13aa5ff-1_all.ipk

opkg install those two and wget with ssl support is needed from the normal repo