Article snapshot taken from Wikipedia with creative commons attribution-sharealike license.
Give it a read and then ask your questions in the chat.
We can research this topic together.
The Kemmelberg is the emotional centrepiece of the race. This edition, the second ascent of the Kemmelberg was addressed via its steepest road. The first ascent was via the traditional route with a maximum gradient of 17%, but the second was addressed via this steeper road, which has a maximum gradient of 23% near the top. Race director Hans De Clercq stated that it is a tribute to the historical significance of the Kemmelberg, as it is that road being used the first time the Kemmelberg was included in the men's race, in 1955. According to COTACOL, a Belgian standard work that has examined and graded every climb in the country, the "new" Kemmelberg ascent is the toughest climb in all Flemish races. They have given it an overall score of 183 points, which is more than the Koppenberg, the Muur van Geraardsbergen or the traditional Kemmelberg road.
The cyclingnews link states that the traditional ascent of Kemmelberg has a 17% average gradient over less than half a kilometer, but in fact, that is its maximum