It has around 1000 ppm ZDDP, which is above the chemical limit for an ILSAC grade (xW20, xW30) oil, hence it's "only" API SL. These limits don't apply to non-ILSAC grades like xW40. So the same add package in a 5W40 can be SN or SP, but in a 5W30 must be SL regardless of the oils quality.
The oil is a full synthetic with ACEA A3/B4, plus the very rigorous OEM approvals of BMW LL-01 and MB 229.5 so it's a very high quality oil. I use it all the time.
It says "API SERVICE SP" inside the donut and "API SL" outside. Which I take to mean that it meets API SP in engine performance testing, but API SL in chemical limits (Phos content).