The xergm package implements eXtensions for Exponential Random Graph Models (ERGM), in particular temporal ERGMs via bootstrapped pseudolikelihood (btergm package) and the relational event model (rem package). It used to include generalized ERGMs for value-edged networks (GERGM package) and calculation of marginal effects for ERGMs (ergMargins package), but these packages were archived on CRAN. It also loads helper functions and datasets in the xergm.common package.
This package used to contain common infrastructure and datasets for several packages. But the constituent packages sometimes failed to be updated, which made it difficult to keep this package on CRAN. Hence, the respective functionality and data were moved into the btergm package. The xergm package is therefore archived because it is now devoid of content. If you read the 2018 article in the Journal of Statistical Software about xergm and are wondering how to estimate TERGMs, please just replace any library("xergm") calls by library("btergm"). So long.
