Thank you for your long-time maintenance of this plug-in. As discussed in the comments on your site, I would like to propose a patch that would allow users to disable category exclusion when an authenticated API request (XMLRPC or REST) is being made. This will improve the plugin behavior for any users who have, over the years, noticed that the plugin prevents external editing tools like MarsEdit, the iOS WordPress app, etc., from accessing posts that are excluded “from the main page”.
I propose that in the interest of making the plugin behave more predictably for new users going forward, the new option should be enabled by default, but that for existing users the new option should be disabled. This will hopefully satisfy most users by making the most obvious (IMO) behavior default going forward, but not changing anything for existing users until and unless they opt in with the check box.
Please see the linked changes which provides the changes proposed:
https://github.com/danielpunkass/ultimate-category-excluder/pull/2/files
Let me know if you have any questions or concerns.
Thanks! Daniel