I have self-hosted Discourse based forum, available over .onion domain only (Hidden Service Version 3). Everything works as expected, however when I connect to the forum with an up to date version of Tor Browser I can see an exclamation mark on the onion icon in the address bar, similar to what you can sometimes see when you have mixed content error with clearnet https connection.
When I click on the exclamation mark I can see actual warning saying:
"Connection not secure. Parts of this page are not secure (such as images)".
It looks like similar to https error, however my forum does not use https in urls, there is no certificates added etc. I have no clue, what does it mean in the world of onion domains. Any ideas?