GitHub - TheMMcOfficial/cups-for-openwrt: If you want to install cups on your openwrt router to share a usb printer or to enable airprint on your old usb/network printer follow these steps.
GitHub - syb999/openwrt-musl-cups
GitHub - krzys-h/openwrt-samba4_with_cups: CUPS and samba4 with CUPS support packages for OpenWRT
How to compile cups into OpenWrt? - For Developers - OpenWrt Forum