clustered covariance matrix from felm (lfe package) - r

I would like to extract the clustered covariance matrix from a felm object of the lfe package. When I use
felm(y~x|z|0|q,data)$vcv
I get the non-clustered covariance matrix and the standard errors computed from the covariance matrix and standard errors reported in the summary() function differ. Does anyone know how to extract the clustered covariance matrix?

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