What is not known. It goes here and it is not glossed over.
saca_el_golpe_del_guion (0x4C02) builds a pointer in (0xE252) out of four groups of eight triples at 0x6858, indexing it with (0xE207) & 3 times twenty-four and (0xE254) & 7 times three. The three steps of each script are read, and so is the fact that on odd steps it tosses a coin between the byte before and the byte after (0x4C40). What is not measured is whether the eight triples of each group make up a recognisable repertoire of combinations —a one-two, a hook— or are just a list.
Each damage level's threshold comes from 0x5445 —0x1A, 0x14 and 0x10— for levels 5, 6 and 7, and it is 0x10 below level 5. That level 5 has the highest threshold of the three breaks the monotonic run and no explanation has been found inside the code. It may be deliberate —a breather at the halfway point— or it may be a value put in by eye.
lee_el_teclado (0x44A8) takes bit 6 of keyboard row 7 —which is SELECT— and puts it into bit 5, which 0x4467 folds into bit 4, the punch. It works as a second button, but it has not been checked in the emulator whether the game does anything different with it or it is only convenience.
tools/archivo_de_figuras.py explains 20,312 of the 20,338 bytes of 0x707E..0xBFF0 by walking the four tables and their 76 figures, each with the piece count the Z80 really walks. 26 bytes in two gaps are left: eight in front of the first table (0x707E) and eighteen right before Konami's hidden mark (0xBFDE). They are declared as data and nobody reads them along any traced path, but what they are is not known.