To open the looped through connection of the lines first pull the open end of the yellow line all the way through the loop of the red line

The yellow line is the one that was connected to the brake handle. It now has one end open.

After the line has been pulled through the loop of the red line, pull the red line through the loop of the yellow line from the side that goes further up to the glider to remove it from the yellow line

Again! Do not pull too fast as the line coating could get damaged.

The yellow line is now free.