Borrow, Absorb and Buy Collateral Diagram

Borrow

There is no borrow() function: a borrow is withdraw(USDC) that takes the signed principal below zero
A withdrawal that stays positive skips the borrow branch: no oracle call and no priceUpdate needed
The resulting debt must be at least MIN_BORROW, so dust debts are never created

Absorb and buy

absorb pays the absorber nothing; the incentive is the discount in buyCollateral
A surplus over the debt is credited to the absorbed account as supply; a shortfall pushes reserves down, possibly below zero
Buyer discount = storeFrontPriceFactor × (1 − liquidationFactor), never above the absorb penalty

Scope

One collateral asset (WETH) shown; the price push and seize loops run over every asset in the account's assetsIn bitmap
Withdrawing collateral runs the same health check when the account has debt
supply repays debt first when the account is negative; a full repay uses amount = type(uint256).max
Token transfers sit on the call that makes them: WETH pulled by supply, USDC sent by withdraw, USDC in and WETH out in buyCollateral