Resolved: There was an error downloading the plugin list
I decided to try once again to use the plugin manager to get the TextFX Characters plugin.
Ran Plugin Manager... it needed to be updated.
After the update:
- It has ads: "Plugin list hosting generously provided by" (some business I'd like to DDOS)
And message:
There was an error downloading the plugin list. Please check your internet connection, and your proxy settings in Internet Explorer, Edge or Chrome.
So we went backwards.
I changed the setting that says "Force HTTP instead of HTTPS for downloading Plugin List". Restarted Notepad++ and was then able to download the plugin list and install the TextFX Characters plugin.