SALT stands for Scriptable Audio Library Tool and its goal is to go from raw recording to kontakt or hise or other sampler format much more efficiently than you could do even with all the REAPER scripts and actions in the world. REAPER is not suitable for many tasks, prone to frustrating mistakes, easily costing you hours of time trying to figure out where you went wrong along the way or trying to find that needle in the haystack where you made a mistake. These little mistakes can ripple out to bigger problems down the road. It's important to have a customizeable tool and informative interface that prevents these kinds of problems.
Looping, autotuning, spectral editing, file management, sampler patch creation, REAPER project reading and rendering, etc. There is no release date and it is closed source. It is not for sale because it is lacking in many areas. The only way to get access to it is to talk to me on skype and support development via monthly funds or a large sum, won't be worth it for you unless you plan on using it extensively to support your sample library business/income.