Well Castrol have a number of versions of "Agri" oils, they have been around for a VERY long time and are very popular in Australia and eleswhere
Molakule - you said;
"Appears to be another 15W40 HDD oil. Not much else to say about it."
Well, I can say that they are VERY good products as Castrol make some of the very best diesel engine oils made anywhere! I can justify these comments by extensive field testing and use over some decades!
Castrol's "Agri" oils carry Approvals and endorsements from many of the major engine and equipment manufacturers. In the correct applications they rate amongst the best available
Those that have a VapourPhase Inhibitor work extremely well in equipment that is idle for weeks/months during operational off seasons. This is especially so at the extremes of climate
Steiner - enjoy an excellent product