The default configuration for the share links site setting on Discourse includes Facebook:
Because of this, Facebook Container shows a warning & disables the button on most Discourse sites by default:
How the Container works:
Now, I’m not sure how much tracking is done here or if it’s a false positive but does it make sense to remove Facebook from the default configuration for that setting?
There is zero tracking happening. The icon is just Font Awesome, served from the site own domain or CDN. This is a bug on this Firefox custom extension.
I’d say no. There is no tracking until you click on the button. And after you click on a button with a Facebook logo inside a “Share this” modal, it is reasonable that you will be sent to Facebook.
I’d recommend using the Multi-Account containers extension instead.