Found the following significant warnings:
  Rd warning: /home/hornik/tmp/scratch/Rtmp4FwFUX/R.INSTALL4e265b0495df/handlr/man/citeproc_writer.Rd:13: file link ‘toJSON’ in package ‘jsonlite’ does not exist and so has been treated as a topic
  Rd warning: /home/hornik/tmp/scratch/Rtmp4FwFUX/R.INSTALL4e265b0495df/handlr/man/citeproc_writer.Rd:16: file link ‘toJSON’ in package ‘jsonlite’ does not exist and so has been treated as a topic
  Rd warning: /home/hornik/tmp/scratch/Rtmp4FwFUX/R.INSTALL4e265b0495df/handlr/man/citeproc_writer.Rd:18: file link ‘toJSON’ in package ‘jsonlite’ does not exist and so has been treated as a topic
  Rd warning: /home/hornik/tmp/scratch/Rtmp4FwFUX/R.INSTALL4e265b0495df/handlr/man/codemeta_writer.Rd:13: file link ‘toJSON’ in package ‘jsonlite’ does not exist and so has been treated as a topic
  Rd warning: /home/hornik/tmp/scratch/Rtmp4FwFUX/R.INSTALL4e265b0495df/handlr/man/codemeta_writer.Rd:16: file link ‘toJSON’ in package ‘jsonlite’ does not exist and so has been treated as a topic
  Rd warning: /home/hornik/tmp/scratch/Rtmp4FwFUX/R.INSTALL4e265b0495df/handlr/man/codemeta_writer.Rd:18: file link ‘toJSON’ in package ‘jsonlite’ does not exist and so has been treated as a topic
  Rd warning: /home/hornik/tmp/scratch/Rtmp4FwFUX/R.INSTALL4e265b0495df/handlr/man/rdf_xml_writer.Rd:12: file link ‘jsonld_to_rdf’ in package ‘jsonld’ does not exist and so has been treated as a topic
  Rd warning: /home/hornik/tmp/scratch/Rtmp4FwFUX/R.INSTALL4e265b0495df/handlr/man/schema_org_writer.Rd:13: file link ‘toJSON’ in package ‘jsonlite’ does not exist and so has been treated as a topic
  Rd warning: /home/hornik/tmp/scratch/Rtmp4FwFUX/R.INSTALL4e265b0495df/handlr/man/schema_org_writer.Rd:16: file link ‘toJSON’ in package ‘jsonlite’ does not exist and so has been treated as a topic
  Rd warning: /home/hornik/tmp/scratch/Rtmp4FwFUX/R.INSTALL4e265b0495df/handlr/man/schema_org_writer.Rd:18: file link ‘toJSON’ in package ‘jsonlite’ does not exist and so has been treated as a topic
See ‘/home/hornik/tmp/R.check/r-devel-gcc/Work/PKGS/handlr.Rcheck/00install.out’ for details.