In plain English
Take the MVRV ratio (market vs cost basis) and ask how many standard deviations it sits from its own history. That is a z-score: 0 is typical, negative is cheaper than the sample mean, positive is richer.
This particular series is compressed near 0 after 2012 because the full-history mean/σ is dominated by early outliers. Read the sign and the zone chips, not a Woobull-style −0.5 / +7 playbook.
Math and metrics
On-chain pack `v` is a full-history z of the MVRV ratio (collector enrichFromRealized, source: realized). It is not Woobull (MV−RV)/σ(MV) — this plate does not invent that.
z_t = (MVRV_t − mean_hist(MVRV)) / σ_hist(MVRV) as published in chain.onchain['mvrv-z'].
After 2012 the series sits near 0; negative ≈ cheaper than the sample mean. Zones on the pane are signed; forward chips use a tighter split around 0.