Explanation is in the README:

> The intention behind this repository is to make source code of the Estonian online voting system available for public review.

> The repository is not used for active development, but will be kept up to date, so the code that can be found here is the code that is used for election.

from README

The repository is not used for active development, but will be kept up to date, so the code that can be found here is the code that is used for election. As the voting system used for legally binding elections must strictly follow the legislation, the actual development of Estonian I-voting system and I-vote verification application is supervised by State Electoral Office of Estonia. Please refer to www.valimised.ee for further information.