The vertices in quantized mesh files encoded using the lat/lon values of the corners of a tile but these values are not directly stored in file. Is there a way to compute the lat/lon extents used to compute the vertices? Can the BoundingSphere values and Center values be used to compute the original extents?
The extent is implicitly defined by the tile x, y, level coordinates. Take a look at GeographicTilingScheme.
There’s not enough information in the quantized mesh file itself to compute the extent, you have to know the tile’s coordinates.