See : TomasMahdal/MapyCZAerials#5
TomasMahdal/MapyCZAerials#5 (comment)
The Mapy.cz API can be used for free only in the way described in the documentation, i.e. using prepared Javascript libraries.
Direct access to Mapy.cz resources is not allowed (and never has been in the past). This includes e.g. linking map tiles to Leaflet, direct calls to the server function for whispering, etc...)
See : TomasMahdal/MapyCZAerials#5
TomasMahdal/MapyCZAerials#5 (comment)