For future use, hard to redo things in terms of it r/n but a bit later surely possible.

game/engines/default/engine/LogDisplay.lua

@@ -86,9 +86,10 @@ function _M:resize(x, y, w, h)
 end
 
 --- Returns the full log
-function _M:getLog(extra)
+function _M:getLog(extra, timestamp)
 	local log = {}
-	for i = 1, #self.log do 
+	for i = 1, #self.log do
+		if timestamp and self.log[i].timestamp <= timestamp then break end
 		if not extra then
 			log[#log+1] = self.log[i].str
 		else

game/engines/default/engine/UserChat.lua

@@ -536,12 +536,13 @@ end
 ----------------------------------------------------------------
 
 --- Returns the full log
-function _M:getLog(channel, extra)
+function _M:getLog(channel, extra, timestamp)
 	channel = channel or self.cur_channel
 	local log = {}
 	if self.channels[channel] then
 		for _, i in ipairs(self.channels[channel].log) do
-			local tstr 
+			if timestamp and i.timestamp <= timestamp then break end
+			local tstr
 			if i.kind == "whisper" then
 				tstr = tstring{{"color", 0xcb,0x87,0xd2}, "<", i.name, "> "}
 			elseif i.kind == "join" then