If you just want to find ores easily, use the "Spectator Mode" ( /gamemode spectator ) in your own world. It offers xray vision without messing with texture files.
If you are testing this in a controlled environment, look for these community classic names. xray texture pack 188 work
If you see through the map but cannot see ores, the server is using a anti-xray plugin. Performance: If you just want to find ores easily,
: Many multiplayer servers use Anti-Xray plugins (like those built into Spigot or Paper ) which "obfuscate" ores by turning them into fake blocks until they are directly exposed to air. xray texture pack 188 work
To clarify: