It is based on the original FFT 1.1 and 1.2 patches by Philsov. All the changes that 1.3 makes to the game can be found in this website. It is a very different experience from the original game.
It greatly increases the difficulty of the game and re-balances it by tweaking items, skills, jobs, and giving the enemies the player faces more options, which unlocks the AI's true potential. Final Fantasy Tactics 1.3 is a modification of Final Fantasy Tactics by Archael.
