So how do I configure a project exactly ?

[GrosSacASac]

The readme leaves me clueless, the https://github.com/nodejs/corepack/blob/main/DESIGN.md says it is "engines": {
"pm": "yarn@^2.0.0"
} and the node doc says {
"packageManager": "@"
}
so which one is it ?

[arcanis]

packageManager. I'll update the readme to reference that. Note that it must be an exact version, not a range.