I would call it a D+7 poll, leaners should fall into the respective D and R buckets
The "leaners" in most polls would be "leans Democrat" or "leans Republican". In this one they have that category roughly covered by "not-strong Democrat" and "not-strong Republican". The word "lean" was used in an even less party affiliated description of "Independent/Leans Democrat" or "Independent/Leans Republican". Considering these latter as Democrat and Republican would make the Independent sampling absurdly low. 13% if I recall correctly (the results are not handy atm).