You can look through the roof in 1.13.2 and 1.8 I believe they have the same glitch on other versions.

You can look through the roof by going down to cobblestone once you've done that create a straight 1x2 pathway so you can fit. When you have done that go into third person, look up until your camera zooms in and start walking/running you will have the effect of being able to make it be X-Ray this effects Multiplayer servers and does effect single player.

Be aware this glitch does not do much harm it is very bad at finding stuff other than bases.