A view homography file contains a 3x3 homography matrix to apply to an image. A view homographies file contains a view homography for each view index in a dataset.
The homography matrix is a projective transformation in homogeneous coordinates, which maps pixel positions of the image to a new position.
It can be applied to one image using misc/apply_homography. A border (positive or negative) such that the resulting images do not get cropped, can be found using misc/homography_maximal_border. This works either for one view homography, or one border for the whole set of view homographies.