pfctl -sm shows pktdelay-pkts as hard limit, but where to configure?

Hello!

I am still going through the hard limits in pf.conf, and with pfctl -sm
I can see:

pktdelay-pkts hard limit 10000

I did discover in /usr/include/net/pfvar.h:
#define PF_PKTDELAY_MAXPKTS 10000 /* max # of pkts held in delay
queue */

Is it ever necessary to change pktdelay-pkts? I can't seem to find where
to configure it.

Thank you,

Paul