192 represents the descriptor length ,9494 represent the Number of key-points you have in the file. The other line consists of [WORD_ID] [X] [Y] [A] [B] [C] X and Y is the feature centroid and A, B, C define the parameters of the ellipse in the following equation A*(x-X)^2 + 2*B*(x-X)(y-Y) + C(y-Y)^2 = 1
You can check the official website for the formate Here If you are using VLfeat package you can read here how to read the file in Oxford format. If you are very curious how the file formate is read in VLfeat vl_ubcread function. Here is the code.