Response field legacyValue removed

What changed

Reads of this field return undefined, and the failure surfaces wherever that value is used rather than at the call.

Affects GET /v10/projects/{idOrName}/env.

Who is affected

Code that reads GET /v10/projects/{idOrName}/env (legacyValue).

Before and after

Code that breaks

// response.legacyValue is now undefined
const legacyValue = response.legacyValue;

Based on Vercel’s published API specification. How severity is decided.