There is a warning which tells that Rule Unit is experimental
https://docs.jboss.org/drools/release/7.64.0.Final/drools-docs/html_single/#_rule_units

But we should clearly tell it in other sections as well.

https://docs.jboss.org/drools/release/7.64.0.Final/drools-docs/html_single/#drl-rule-units-con_decision-engine
https://docs.jboss.org/drools/release/7.64.0.Final/drools-docs/html_single/#drl-rule-units-con_drl-rules

Rather simply drop the section in Drools 7 docs?