https://www.sco.com/developers/gabi/latest/revision.html specifies

> Second draft published May 3, 1999. > ... > New dynamic section tags DT_RUNPATH and DT_FLAGS added. Dynamic section tag DT_RPATH moved to level 2.

In glibc, DT_RPATH and DT_RUNPATH have different semantics regarding precedence related to LD_LIBRARY_PATH. In FreeBSD rtld and musl, DT_RPATH and DT_RUNPATH are equivallent.