Circle-with-brackets usually means a brake warning (think brake drum and shoes).

Probably the pad wear warning indicator. If they've just hit the sensor, it'll come on when you brake and go off when the pads move away from the disks.

Alternatively, it could be indicating a low brake fluid level. That could flash on and off depending which direction you're turning or under braking / acceleration, depending on how the float sensor is positioned.

Check the fluid level first and if that's ok, it's probably worn its pads down.