If you are "not a normal user", then you should understand that I currently do not have the ability to hide tabs because of the limitations of the Firefox WebExtensions API.
If you are "not a normal user", you could go into the settings and remove the checkbox "Enable fast group switching" - and this will disable the functionality that you did not like so much, namely: the URL like "moz-extension://...url=...". You have 2500 tabs - I understand what you have a problem.
About the fact that when you delete the extension there are tabs with the prefix moz-extension - this bug I'll postfix, thank you for finding it.
Thanks for your feedback