Found the following Rd file(s) with Rd \link{} targets missing package
anchors:
  plot.ps.xgb.Rd: ggplot
  ps.xgb.Rd: xgboost
Please provide package anchors for all Rd \link{} targets not in the
package itself and the base packages.
Found the following Rd file(s) with Rd \link{} targets missing package
anchors:
  plot.ps.xgb.Rd: ggplot
  ps.xgb.Rd: xgboost
Please provide package anchors for all Rd \link{} targets not in the
package itself and the base packages.
Found the following Rd file(s) with Rd \link{} targets missing package
anchors:
  plot.ps.xgb.Rd: ggplot
  ps.xgb.Rd: xgboost
Please provide package anchors for all Rd \link{} targets not in the
package itself and the base packages.
Found the following Rd file(s) with Rd \link{} targets missing package
anchors:
  plot.ps.xgb.Rd: ggplot
  ps.xgb.Rd: xgboost
Please provide package anchors for all Rd \link{} targets not in the
package itself and the base packages.
Package unavailable to check Rd xrefs: ‘twang’