Explain how characters work in mcl_signs

mods/ITEMS/mcl_signs/README.txt

@@ -1,9 +1,12 @@
 Mod based on reworked signs mod by PilzAdam:
 https://forum.minetest.net/viewtopic.php?t=3289
 
-License of code: WTFPL
+License of code and font: MIT License
 
-License of textures: See README.me in top directory.
+Font source: 04.jp.org, some modifications and additions were made (added support for Latin-1 Supplement)
+Original font license text states: “YOU MAY USE THEM AS YOU LIKE” (in about.gif file distributed with the font)
+
+License of textures: See README.me in top directory of MineClone 2.
 
 License of models: GPLv3 (https://www.gnu.org/licenses/gpl-3.0.html)
 Models author: 22i.

mods/ITEMS/mcl_signs/init.lua

@@ -1,11 +1,20 @@
 local S = minetest.get_translator("mcl_signs")
 local F = minetest.formspec_escape
 
--- Font: 04.jp.org
+-- Load the characters map (characters.txt)
+--[[ File format of characters.txt:
+It's an UTF-8 encoded text file that contains metadata for all supported characters. It contains a sequence of info blocks, one for each character. Each info block is made out of 3 lines:
+Line 1: The literal UTF-8 encoded character
+Line 2: Name of the texture file for this character minus the “.png” suffix; found in the “textures/” sub-directory
+Line 3: Currently ignored. Previously this was for the character width in pixels
+
+After line 3, another info block may follow. This repeats until the end of the file.
+
+All character files must be 5 or 6 pixels wide (5 pixels are preferred)
+]]
 
--- load characters map
 local chars_file = io.open(minetest.get_modpath("mcl_signs").."/characters.txt", "r")
--- FIXME: Support more characters (many characters are missing)
+-- FIXME: Support more characters (many characters are missing). Currently ASCII and Latin-1 Supplement are supported.
 local charmap = {}
 if not chars_file then
 	minetest.log("error", "[mcl_signs] : character map file not found")