This mod is a slight rework of the Mystcraft integration in the 1.7.10 version of OpenComputers for 1.12.2. It simply adds several additional values to the data you get when analyzing Pages, Linking Books and Age Books, such as the Symbol on a page and the dimension name for Linking and Age books.
It really doesn't do much else. The resulting values are identical to the 1.7.10 version, so programs should still work.