That is webcore which used to be the most powerful scripting tool for SmartThings. It ran as a smartapp inside your groovy shard (tenant) in SmartThings.
Unfortunately it and the rest of the groovy infrastructure is on its way out. At this point only a few months left.
All the automation in ST is now based on the rules api you can access the rules api directly instead of the rule editor. See here for more information.
No rules you created in the UI are not available for editing by RulesAPI and vice versa (ST design decision). No there’s no visual editor for the rules api. Instead they are directing people to the IDE of thier choice in concert with a CLI for SmartThings (you’ll see it in the thread)
SharpTools also has an advanced automation editor available but i have not used it and cannot speak to its features.