/usr/share/fpcsrc/2.6.2/rtl/haiku/ is in fpc-source-2.6.2 2.6.2-8.
This file is owned by root:root, with mode 0o755.
..
/usr/share/fpcsrc/2.6.2/rtl/haiku/Makefile.fpc
/usr/share/fpcsrc/2.6.2/rtl/haiku/baseunix.pp
/usr/share/fpcsrc/2.6.2/rtl/haiku/bethreads.pp
/usr/share/fpcsrc/2.6.2/rtl/haiku/classes.pp
/usr/share/fpcsrc/2.6.2/rtl/haiku/errno.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/errnostr.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/i386/
/usr/share/fpcsrc/2.6.2/rtl/haiku/i386/sighnd.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/osdefs.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/osmacro.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/ossysc.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/ostypes.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/pthread.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/ptypes.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/settimeo.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/signal.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/suuid.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/syscall.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/syscallh.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/sysconst.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/sysheap.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/sysnr.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/sysos.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/sysosh.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/system.pp
/usr/share/fpcsrc/2.6.2/rtl/haiku/termio.pp
/usr/share/fpcsrc/2.6.2/rtl/haiku/termios.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/termiosproc.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/unixsock.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/unxconst.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/unxfunc.inc
/usr/share/fpcsrc/2.6.2/rtl/haiku/unxsockh.inc