I see the following references to "Physical Damage":
# Sledgehammer of the Vælkyr: +20% Physical Damage (currently approximated with Weapon Damage)
Sledgehammer of the Vælkyr Muscle: +23, Critical Hit Percent: +10, Class: "Seal Clubber", Weapon Damage Percent: +20
# hobo stogie: +100% Physical Damage against Hobos
hobo stogie Single Equip, Weapon Damage Percent: [100*zone(Hobopolis)*(1-loc(Sewer Tunnels))]
# kumquartz ring: +200% Physical Damage (currently approximated with Weapon Damage)
kumquartz ring Single Equip, Weapon Damage Percent: [200*zone(The Candy Diorama)]
# sea mantle: +150% Physical Damage (Underwater Only)
sea cape Moxie Percent: +5, Maximum HP: +30, Maximum MP: +30, Initiative: [50*(zone(The Sea)+loc(The Sunken Party Yacht))], Critical Hit Percent: [15*(zone(The Sea)+loc(The Sunken Party Yacht))]
# sea mantle: +150% Physical Damage (Underwater Only)
sea mantle Muscle Percent: +10, Maximum MP: +50, Weapon Damage Percent: [150*(zone(The Sea)+loc(The Sunken Party Yacht))]
# Bloody Grin: +500% Physical Damage
Bloody Grin Experience (Muscle): [25*zone(Twitch)]
# Brass Loins: Physical Damage +100% (in Dreadsylvania only)
# Brass Loins: Triple bonus damage against Bugbears, Werewolves, Zombies, Ghosts, Skeletons and Vampires
# The Captain's Hammer: +50 Physical Damage (when Unarmed)
As you can see, for several of those we "approximate with Weapon Damage" for others, we do not.
I'm curious about how item enchantments are generated in desc_item.php. If they are generated on the fly, then "pctdamagebonus" of 500 is displayed as "Physical Damage +500%", and whatever is on Boris's helm (for example) which displays as displays as "Weapon Damage +50%" is something else.
Weapon of the Pastalord does Physical Damage, no? If so, the sea mantle should improve it underwater. And, since it is not a "weapon" (I assume), items that grant Weapon Damage Percent would not improve it. I imagine we could use that to determine if there are, in fact, two different enchantments, and we should add Physical Damage Percent.