add setting `enable_non_player_action_log`

minetest.conf.example

@@ -75,3 +75,6 @@ default:torch 99,default:cobble 99
 # Enable cloud variation by the 'weather' mod.
 # Non-functional in V6 or Singlenode mapgens.
 #enable_weather = true
+
+# If enabled, non-player actions are logged
+#enable_non_player_action_log = false

mods/default/functions.lua

@@ -758,11 +758,21 @@ function default.can_interact_with_node(player, pos)
 	return false
 end
 
+local non_player_action_log = minetest.settings:get_bool("enable_non_player_action_log") or false
+
 function default.log_action(player, pos, message)
-	-- only log actions of real players
+	local who = player and player:get_player_name() or "(something)"
 	if player and not player.is_fake_player and player:is_player() then
-		minetest.log("action", player:get_player_name() ..
-			" " .. message .. " at " .. minetest.pos_to_string(pos))
+		-- log action of real player
+		minetest.log("action",  who .. " " .. message .. " at " .. minetest.pos_to_string(pos))
+	elseif non_player_action_log ~= false then
+		-- log action of non real player
+		if player and player.is_fake_player and type(player.is_fake_player) == "string" then
+			who = who .. "(" .. player.is_fake_player .. ")"
+		else
+			who = who .. "(*)"
+		end
+		minetest.log("action",  who .. " " .. message .. " at " .. minetest.pos_to_string(pos))
 	end
 end
 

settingtypes.txt

@@ -75,3 +75,6 @@ river_source_sounds (River source node sounds) bool false
 #    Enable cloud variation by the 'weather' mod.
 #    Non-functional in V6 or Singlenode mapgens.
 enable_weather (Enable weather) bool true
+
+#    If enabled, non-player actions are logged
+enable_non_player_action_log (Log non-player action) bool false