Having given Lylla’s cybernetics a going over, Rocket teaches the otter the basics of cyber-maintenance. Just because the servos and such are internal doesn’t mean they can’t develop problems. Both the Uplifts have experienced pain from cybernetics issues and routine maintenance is just good sense. Lylla’s “programming” didn’t include mechanical expertise as Rocket’s did but there’s no reason she can’t learn, just as she’s trying to teach him some social niceties, something his force-learning programming completely neglected.