CYP19A1
CYP19A1 aromatase — the molecular target that 1 compounds in the wiki act on.
In one line: The enzyme that turns testosterone into oestrogen — blocked to control oestrogen on hormone cycles.
CYP19A1 (aromatase) is the enzyme that converts some of your testosterone into oestrogen. Men on testosterone therapy or steroids can see oestrogen climb too high (causing bloating and breast tissue), so "aromatase inhibitor" drugs (like anastrozole) block this enzyme to keep it in check.
The important nuance: the goal is balance, not zero. Crashing oestrogen causes just as many problems — bad joints, low libido, poor mood — as having too much. It's a dial to tune, not a switch to slam off.