DCO GitHub UI
This browser extension adds DCO Signed-off-by line to commits made with the GitHub browser UI.
Add your full DCO signoff line in the extension options:
Your signoff should now prepopulate in the GitHub UI commit optional extended description textarea:
What is DCO?
git help commit:
-s, --signoff Add Signed-off-by line by the committer at the end of the commit log message. The meaning of a signoff depends on the project, but it typically certifies that committer has the rights to submit this work under the same license and agrees to a Developer Certificate of Origin (see http://developercertificate.org/ for more information).
For CLI git, see this gist.