Thank you again! I was not aware that jekyll -h could be augmented with a subcommand! Now I see the many options, also for the other subcommands. And I’ve left off the URL.
Interesting: while --livereload can be placed into _config.yml as livereload: true, this does not seem to be the case for --open-url.
This great community is a major asset of jekyll!
Best, Michael