Stilly River Sage wrote: When just "mudcat.org" is entered Google adds www and messes up the search.

Google seems to have learned better, now; when I use that technique, it gives identical results for "site:mudcat.org" and "site:https://mudcat.org" -- I just ran tests to verify this.

Still, you are probably right that it's better to use the true and correct domain name, just to get in the habit. Also, the search was 0.03 seconds faster with the correct name. :-)