Override Mode instead of DRS — does anyone actually understand how it works on track?

Two months into the new regs and I still find myself confused watching on TV about when a driver actually has Override available versus when they're just... going fast. My understanding: it's an extra electrical deployment allowance when you're within a second of the car ahead, similar spirit to DRS but through the power unit rather than a rear wing flap. No physical drag reduction, just a bigger electrical punch out of the corner before it. Can anyone who's actually read the technical regulations in full confirm I've got that roughly right? The broadcast graphics are not helping.