If you upgrade DragonFly and one of the shared libraries used by pkg gets updated, you can’t run pkg until you get files, but pkg is the program you use to bring in new files.  This chicken-and-egg problem is solved with pkg-static, a version of pkg built without shared libraries.

You may have noticed some format flip-flopping between pkg and pkg-static if you had to run it after the most recent DragonFly upgrade; that is fixed.  There’s a larger issue of certificate installation identified there; I don’t know a solution to it, but I do want to mention this for next time pkg breaks for someone – pkg-static will work as backup, including to bring in a new version of pkg.