Minecraft wiki entry for Ambience, associated text: When "Cave 14" is viewed in a spectrogram, it appears to show the face of a creeper.
Cave ambience is the only ambience that has subtitles.
"Basalt Deltas click" is likely based on the sound a Geiger counter makes when in the presence of radiation, despite neither Geiger counters nor radiation existing in vanilla Minecraft.
"Cave 1,5, and 13" can also be heard in lower pitches. The pitch can range from 0.65x to 1.00x.
"Cave 5 and 13" also sound a little similar, but they are played with different speeds. Also the sound for "Cave 5" sounds like a low-ringing bell while "Cave 13" sounds like an intense brush of wind.
Although the mood algorithm works in all vanilla dimensions since Java Edition 1.16, due to the mood system isn't programmed properly for the End ambience sounds to be played in the End, so the Overworld cave ambience sounds could be played in the End instead.[verify]
"Warped Forest Additions 1-5" are a mix of vanilla Enderman sounds and those of the Enderman from Minecraft Dungeons.
"Warped Forest Mood 9" is actually a slowed-down and reverberated idle sound of the witch.