lmnewgen - Program that generates lm_new.c, which, in turn, is used to generate lm_new.o (UNIX) or lm_new.obj (Windows).
lmnewgen -s tells lmnewgen to produce a short/simplified/unobfuscated version of lm_new.c (the FNP version of identity data), from memory this has been suggested to some customers who want to use tamper resistant approaches (other than SDTs) as otherwise it gets modified at runtime which can be detected as a tamper by things like Arxan. It is recommended to not use this option.
lmnewgen -bfixedis referred as borrow fixed. It is mostly used by customers to generate same lm_new.c file across FNP versions. This feature helps to achieve backward compatibility across different client versions.