From time to time, it can be useful to know who signed a given macOS application.
You can do that like so:
$ cd /tmp/codesign
$ codesign --display --extract-certificates $(which curl)
// This will create some files in the current directory
codesign0 codesign1 codesign2
$ qlmanage -c public.x509-certificate -p codesign*
qlmanage will pop open a Finder preview window with the metadata for the attached signature