What is the `pau` phoneme supposed to represent phonetically?

The pau phoneme, which seems to represent a “pause”, doesn’t seem to have a phonetic justification for its existence. So far when I used this phoneme, it sounds like a random sonorant. What is it phonetically, and why is it usable for every supported language?

It’s one of the phoenemes that was excluded from the list published on the Dreamtonics website (Synthesizer V Studio Help Resources | Dreamtonics株式会社).

This means it’s most likely just a holdover from early development, similar to the English q phoneme which was Eleanor Forte lite’s glottal stop, but is unimplemented for voice databases that followed which use cl instead.