An interesting infrastructure project and as I understand it, the company has an official registration in Estonia? What country is the team from?
The team is from different countries as I see in their LinkedIn profiles. But most of them pointed in Spain, maybe this is their base. Need to ask it to the team directly.
It appears the team has a registered office in Estonia but they don't seem to be officially endorsed by the Estonian government, which makes the wording of the OP confusing and potentially misleading.