LISTSXP.Rd
LISTSXP is an object-like macro defining the SEXPTYPE type of pairlist objects.
LISTSXP
SEXPTYPE
pairlist
#define LISTSXP 2 /* lists of dotted pairs */
In Rinternals.h.
https://cran.r-project.org/doc/manuals/r-patched/R-ints.html#SEXPTYPEs
SEXPTYPE, TYPEOF