Per
#4924, the "main" branch should now be the source and destination of all pull requests. This new workflow is a dramatic simplification. In essence, everything happens in "main". All other branches exist only to create PRs.
The method I used to update main differed from that suggested by the issue. It isn't possible to rename the default branch directly, so I used a three-step process.
Just before deleting the "devel" branch, the gitk app reported that the "main" branch had the same history as the about-to-be-deleted "devel" branch, so we should be good to go.
Please report any problems. All questions, comments, or suggestions are welcome.
Edward