I would appreciate a simpler conceptual explanation for someone not steeped in the Haskell / functional programming world :-)
It was given to a Haskell audience, but not everyone knew Haskell, so I hope it's generally accessible. It describes how Oleg's work fits into the overall history of Haskell effect systems.
Yes, Xavier's book was really interesting. It's here: https://xavierleroy.org/control-structures/
It's missing some subtleties of capability-based effect systems (which Bluefin is). Maybe I should write to him.