Q value from Lc0

[chesskobra]

There are many opening and endgame positions at https://github.com/jhorthos/lczero-trai ... ning-Books Each position has been assigned a Q value (annotated with an Lc0 net). The developer says

Approximate Q guide:
openings with abs(Q) 0.0 to 0.25 are balanced (roughly between -30 and 30 centipawns on the Stockfish scale)
openings with abs(Q) 0.25 to 0.4 are unbalanced
openings with abs(Q) and over 0.4 are very unbalanced

But exactly what do the Q values mean? Is there a mapping from the Q value to the expected score or the probability of winning?