Look Ma, no MAX_PARSE_BUFFER! (At least not in the backend.

src/backend/access/common/indextuple.c

src/backend/access/index/istrat.c

src/backend/libpq/auth.c

src/backend/libpq/hba.c

src/backend/libpq/password.c

src/backend/libpq/portal.c

src/backend/libpq/pqcomm.c

src/backend/libpq/pqformat.c

src/backend/libpq/util.c

src/backend/tcop/postgres.c

src/backend/utils/mmgr/palloc.c

src/bin/pg_dump/common.c

src/bin/pg_dump/pg_dump.c

src/bin/pg_dump/pg_dump.h

src/include/access/ibit.h

src/include/access/itup.h

src/include/libpq/hba.h

src/include/libpq/libpq.h

src/include/miscadmin.h

src/include/postgres.h