BUR #19202 has been approved by @evazion.
create alias patrol_cap -> field_cap
Wikipedia said
A patrol hat, also known as a field cap, is a soft kepi constructed similarly to a baseball cap, with a stiff, rounded visor but featuring a flat top, worn by military personnel...
I prefer aliasing it into field_cap because there is also tag M43 field cap for the distinct WWII German counterpart, and also to make it more searchable among other military item-related tags like field radio or field ration.
post #5959042 depicts WWII-era Finnish military field cap, but does not look like German one.