tmux.SessionOptionValues.UpdateEnvironment

UpdateEnvironment returns materialized "update-environment" as OptionValue with value type OptionValue[SparseArraystring] from session option values; it does not query tmux. Available as STRING since tmux 3.2a; set it with Session.SetUpdateEnvironment or GlobalSessionScope.SetUpdateEnvironment . Its present SparseArray value preserves assigned tmux indexes, including gaps.