[Youden]

The text of the initiative is here: https://www.bk.admin.ch/ch/d/pore/vi/vis555t.html

It's primarily an attempt to control immigration.

At 9.5M, the government has to start limiting the issuance of residence permits and start renegotiating international commitments that drive population growth.

At 10M, the government has to terminate the free movement agreement with the EU.

The right-leaning parties bring up something like this every few years. They always get shot down.