[FIP-442] Optional Early Exit for the Legacy crvUSD/L-FRAX Convex FRAX Vault (4% Fee)

Authors:
Mockingbird

Summary:
This proposal introduces a one-time optional early exit program for the legacy crvUSD/L-FRAX Convex FRAX vault.

Eligible lockers may exit before lock expiry by paying a fixed 4% fee on the amount exited. The 4% fee is the sole economic condition of this optional early exit path.

This proposal applies only to this specific legacy vault.

Background & Motivation:
The crvUSD/L-FRAX Convex FRAX vault is a legacy route after the FRAX to frxUSD stablecoin transition.

This case is specific because:

1. Long-duration locks were entered more than 2 years ago, before frxUSD existed as the supported successor route.

2. Returns were only reasonable during the first few months, then remained very low for a long period, and have been 0% since around August 2025.

3. The supported successor route today is frxUSD/crvUSD, while legacy crvUSD/L-FRAX lockers remain hard-locked in the deprecated route.

Frax has stated that if a controlled sunset is introduced for L-FRAX venues, crvUSD/L-FRAX would be included in a penalty-free exit process. At the same time, there is currently no planned timeline for a full L-FRAX sunset.

This proposal is a limited practical option for this single vault while broader L-FRAX sunset timing remains unresolved.

Proposal Details:
Scope
This FIP applies only to the legacy crvUSD/L-FRAX Convex FRAX vault.
Pool Address: 0x0cd6f267b2086bea681e922e19d40512511be538
Pool URL: https://www.curve.finance/dex/ethereum/pools/0x0cd6f267b2086bea681e922e19d40512511be538/deposit
Vault Address: 0x67CC47cF82785728DD5E3AE9900873a074328658

Eligibility

• All existing lockers in this vault are eligible, including long-duration locks, provided the lock was created before the activation time of the early exit program.

Early Exit Terms

• Eligible users may exit before lock expiry.
• A fixed 4% fee is charged on the amount exited.
• The fee is paid to the Frax treasury.
• The 4% fee is the sole economic condition for using this optional early exit path.
• Participation is voluntary.

Implementation

• Frax/Convex may choose the technical implementation method, activation timing, and program duration, provided the scope and economic terms above are preserved.

Future L-FRAX Sunset

• If Frax later introduces a broader L-FRAX controlled sunset that includes this vault, that process may supersede this optional early exit program for users who have not used it yet.

Vote Options:

• For: Implement the proposal as described
• Against: Do nothing