Description
When writing rules in JSR 223, one ultimately has to access automationManager to do something useful. The presets - Default, RuleSimple, RuleSupport, RuleFactories, ScriptAction and cache - provide some implicit imports and objects (variables). The latter objects enable connecting the JSR223 code with the OH internals and installing some meaningful automation.
As the only way described at https://www.openhab.org/docs/configuration/jsr223.html to install a rule is to use automationManager and thus to import the RuleSupport preset, this preset has always to be included explicitly by the caller. The other items from the preset are not strictly necessary, as they can be obtained by imports. (And the imports are required to move as much code in Groovy as possible under the TypeChecked and CompileStatic annotations).