30.6.5.3.1. SVE spec
ARMv8 architecture reference manual A1.7 "ARMv8 architecture extensions" says:
SVE is an optional extension to ARMv8.2. That is, SVE requires the implementation of ARMv8.2.
A1.7.8 "The Scalable Vector Extension (SVE)": then says that only changes to the existing registers are described in that manual, and that you should look instead at the "ARM Architecture Reference Manual Supplement, The Scalable Vector Extension (SVE), for ARMv8-A."
We then download the zip from: https://developer.arm.com/docs/ddi0584/latest/arm-architecture-reference-manual-supplement-the-scalable-vector-extension-sve-for-armv8-a and it contains the PDF: DDI0584A_d_SVE_supp_armv8A.pdf which we use here.
That document then describes the SVE instructions and registers.