"tag-add issue [tags/]tag" adds a tag, as was noticed before.
"dep-add issue-dst issue-src" will link issue-src in issues-dst's deps/.
"show issue" shows most of issue's information in human friendly way.
+"comment" allows you to conveniently add comment.
comment-list, recfile-export and recfile-export-all produces
recutils'es compatible recfile output, which is machine friendlier.