I'm not sure about this one... Please close if it's correct. In the Logs preferences chapter, under AcquisitionLog (https://koha-community.org/manual/latest/en/html/logspreferences.html#acquisitionlog) "MODIFY_BUDGET: a budget was edited (this does not include clo)" I feel like "clo" might have been "closing a budget"? Unless it's an acronym, CLO, although I'm not sure what it would refer to...
I don't think it's an acronym; like you, I think it could have been "closing a budget". Marking this as needs looking / documenting - but not Academy.