Solvency 2 RI Assets?

So what I am learning about Solvency 2, particularly how to view an insurers balance sheet and I keep coming across an item on the Assets side of the balance sheet called “RI” or “RI Assets”. Only thing I’ve come up with is “Responsible Investment” but that’s a bit of a guess really. Anyone know what it means.

Here’s an example of where it turns up.

https://www.towerswatson.com/assets/pcreserving/Solvency-II-Technical-Provisions.pdf