I am a Swedish citizen. Lived here for almost 40 years. It is a bit unclear to be what the "the Swedish e-government platform" is. Would have been great if they at least could have published which domain name the service has.
I would guess that skatteverket.se, polisen.se, kronofogden.se are among those affected by the leak.
Nothing in particular, based on my understanding CGI a Swedish IT consultant company was hacked, they have contracts for and are the maintainers and developers of a bunch of various government departments IT services.
There is no such thing according to Peder Sjölander, IT Director at the Swedish Tax Agency:
https://www.svt.se/nyheter/inrikes/uppgift-statlig-it-inform...
– Neither our data nor our users' data has been leaked. It is a service we use for e-signatures that has been affected, but there is no data from us or our users there, says
The information that source code was leaked from a joint government e-platform is not true, according to Peder Sjölander.
– There is no such platform. I think the perpetrators in this want people to feel insecure. We feel confident that our data is safe and we have the situation under control before the tax return period opens next week.
It's not going to be a specific service or agency with a domain name, it's going to be services that are either internal and used by employees only, or that are integrated into other systems that you may be interacting with without knowing it.