I suspect this one wasn’t updated anymore. It’s a must for engaging non-technical users on trivial topics to give them confidence.
This is what my instance shows after trying to enable the component:
Error: Undefined mixin. ╷ 58 │ @include sticky; │ ^^^^^^^^^^^^^^^ ╵ theme-entrypoint/mobile.scss 58:7 @import /var/www/discourse/mobile.scss 3:9 root stylesheet