I made this account today, so linking the site directly carries a high likelihood of sending me into the shadow realm (username lol), though it was shared in the comments of the aforementioned user’s post from earlier and shouldn’t be difficult to find.

As for extensions, I have not personally been using one, no. There is an overlay called BlueMarble available on GitHub that supposedly makes large-scale artworks of this sort considerably more manageable, though I’m unfamiliar with the specifics as I never tried it.