What does the x mean on this schematic
Some schematic programs use this as a symbol to show that the pin is specifically not connected to anything.

However, this looks to be a schematic from Eagle.  Eagle requires no such symbol.  Output or passive pins are allowed to not be connected without any electrical rules check error.  You can make a symbol and footprint for anything you want in Eagle, so only the designer knows for sure what this means.  It could mean a test point, but most likely not since there is no component designator.  A bunch of test points on the board are pretty useless unless labeled, so I don't think that's it.  Most likely whoever created that schematic was used to a different schematic program and felt compelled to put Xs there to indicate not connected.  In Eagle, you simply don't connect anything and don't give it a name and it won't be connected anywhere.