Most likely an "arrow damage disable". Good for sieges not for defending.
So i had to figure this out myself.
>open cheat engine and select process "stronghold.exe" as usual.
>Than click "Memory View" (just above addresses)
>Copy "Stronghold.exe+F4FCE" than CTRL+G and paste it > OK
>it finds a
line like Stronghold.exe+F4F...make sure is followed by the add 29 8C 3E 60060000.
>Double click on that line and cancel "sub [esi+edi+00000660],ecx" and just write "nop" >OK
Now arrows on both sides do not effect any damage. Both sides troops still take damage from mele, fire etc. Buildings are destructible. (as i said.. good for sieges)
Don't close "Memory View tab" so u don't lose the line.
>To reenable Arrow damage again just double click on the line again, cancel "nop" and paste "sub [esi+edi+00000660],ecx" > OK
...or restart the game