I think that all formulas in this thread maybe incorrect. I found next formula for this developer here

Metol 17.8 grams
Oxalic Acid 1.7 grams
Potassium Metabisulfite 4.3 grams
Sodium Sulfite 140.0 grams
Pyro 51.2 grams
Triethanolamine 133 ml
Water to make 2 gallons

2 gallons = 7.57l, so we can calculate amount for 1l

Metol 2.4 grams
Oxalic Acid 0.23 grams
Potassium Metabisulfite 0.6 grams
Sodium Sulfite 19 grams
Pyro 6.8 grams
Triethanolamine 18 ml
Water to make 1l

still don't understand why we need Oxalic Acid in formula. pH buffer?