Constant TEMPO_T0_BASE_FEE 

pub const TEMPO_T0_BASE_FEE: u64 = 10_000_000_000; // 10_000_000_000u64

Available on crate feature reth only.

T0 base fee: 10 billion attodollars (1×10^10).

Attodollars are the atomic gas accounting units at 10^-18 USD precision. Basefee is denominated in attodollars.