Here; I shall find the script in a clean rom and then search for it in his hacked engine (just for anyone who doesn't know, the hacked engine is based on the clean patch).
It is just a regular script, so it really doesn't take asm to write. Just a knowledge of all of the specials.
Edit: On a clean FR rom, the PC script is at 0x1A6963. Now I shall search for it in the cleaned rom.
Edit2: Jambo, I was semi-wrong, it does exist in the game at said offset.
However, it is only 156 lines. The script in the regular FR rom is 238 lines. So, I don't know what exactly was removed.... Probably those lines and small snippets of code which are used often by many different scripts.
Edit3: The entire section where you can check your pokedex and all related strings and small code snippets that go along with it have been removed. Did JPAN mess with the specials that deal with this so he took a precaution on it? Or do you think those parts were shared with other scripts?
Edit4: Here are both scripts to save some time: