In general the game should not crash even if some invalid changes are done. Game placement rules validation is a little bit paranoid so you can disable it for some changes if you are sure that it is valid. It also disables resource and feature changes on tiles with improvements, cities, districts and wonders because it most probably break your game in some way.
Validates game placement rules and disables the changes that are not allowed by game rules (for example you can't place crabs on land tiles, or marsh on desert tile etc.). This only check known crash reasons so be reasonable while using this mod.
Does not allow you to make the changes that known to cause crashes.
