They've extended it many times and will likely do again. Countries are added and removed almost every week with short notice. US residents were allowed for a while during the summer. To most extent Sweden just follow recommendations from the EU. For vaccinated travelers it seems like Sweden prefer that they have a digital vaccine certificate that can be validated in the common EU system.
Just a lay-over within the Schengen area will change your status for arrival in Sweden. Arrivals from Schengen (or if you have passed immigration in an EU country) require a test, from Nordic countries not even that. Since airlines might not understand these rules it might be better to do a self-transfer though.