[BIP-89] Enable wstETH/bb-a-usd Gauge [Ethereum]

Summary:

This pool uses the new weighted pool factory and will also be utilizing the new composable stable pool form of bb-a-usd pool to pair with wstETH. This means yield earned by the both halves of the pool will only be taken by the protocol in one iteration. Due to the nature of the assets, this gauge would automatically gain “core pool” status under BIP-19, meaning protocol fees earned by this pool would be used to bribe for votes on it.

References/Useful links:

Link to: • Website • Documentation • Github Page • Communities

Protocol Description:

wstETH is wrapped liquid staked ETH. bb-a-usd is Balancer's AAVE boosted stable token pool token.

Motivation:

Balancer in the short term is strategically position itself as gaining control and market share of the yield bearing asset market through the use of our various pool types. This use case will not only put two yield bearing assets to work but pair greatly in terms of liquidity path for the underlying stable tokens along with wstETH. The yield bearing aspects benefit LPs and the the protocol overall, while permitting a healthy and low friction trade route for aggregators and direct traders to tap in to.

Specifications:

1. Governance: Find more information about governance on Lido’s forum.
2. Oracles: This pool relies on a rate provider for wstETH which has been in use historically. See here.
3. Audits: See here.
4. Centralization vectors: See here for information on this.
5. Market History: See here.
6. Value: Balancer will earn the protocol fee on wstETH and bb-a-usd yield. This configuration is beneficial to all parties involved in market making as noted in the Motivation section.

Link to pool: 0x25Accb7943Fd73Dda5E23bA6329085a3C24bfb6a Link to gauge: 0x651361a042e0573295dd7f6A84dBD1DA56DAc9D5

*Edit of rate provider oracle to correct link.