The instructions in this category, are the "primitive" instructions that drive the SPLat Expansion Framework. It is extremely unlikely that you will need to use them or worry about them. These instructions are used by the programming software to "synthesise" instructions for SPLat peripherals, for example the LCD (OBLCD_ instructions). They are included here for completeness.
(When we make custom UV peripherals, it is less likely we will create high level instructions to match. In those cases we supply sample SPLat code using these primitives.)