As per the title - there is no 6.3 native 'Executive Summary' report in v6.3,
You *can* create a legacy v6.2 type ES report , that looks the same as the 6.2 reports, but there is no native 6.3 report equivalent, and there don't appear to be any suitable report parts or templates to re-create a complete 6.2 style ES report.
I would have expected an Executive Summary report template in 6.3 format that at least roughly paralleled the 6.2 information set. for now, I'm sticking to the 6.2 legacy format, until I can figure out how to make a 6.3 report that at least rougly parallels the information presented by the 6.2 template.
In fact, in 6.3 there are many report template categories that are blank. e.g. nothing under Backup, discovery, Executive on Inventory, for example. Why have these folders if there are no reports within? Or am I missing something?? Perhaps Kaseya intends to populate these later?