Measured against the high-water mark as it stood before the session, so the line is not clamped at zero: below it is drawdown, above it a session that set a record. The width of each trough is how long the account took to earn the loss back.
Sleeve totals are the backtest's own per-bot attribution, scaled with the account on the compound arm.
Many small gains funding occasional large losses: the 1st and 99th percentiles are not mirror images, which is the premium seller's signature.
Each session's P&L as a percent of the capital at risk that day (the daily return), with the account after it and the high-water mark it is measured against. A tax payment is shown on the session it is taken from.