This plane is intended to replace the Su-27 series, and it now appears that
Russia and India are in a 50-50 workshare.

I’m not entirely sure what this would mean, though the Indians are looking to use this aircraft on their carrier.

The company-to-company discussions ffollow an October 2007 intergovernmental agreement between Russia and India signed an on the cooperative development of a fifth-generation multi-role fighter. “This will be 50/50 cooperation in terms of intellectual property, resources and money,” said [Sukhoi CEO Mikhail] Pogosyan.

It appears that the Indian variants will have entirely Indian avionics, which is likely the result of Indian industrial policy.

In developing independent avionics, they may have an opening with upgrades of the aircraft sold to 3rd countries.

As to the 50/50 split, my guess is that this is more of offset numbers than real sharing. This is the crown jewels of Russian aerospace.

A quick note, the fact that the project is called the T-50 means that it has some variant of a delta wing. Were it swept wing, it would be something like S-50, which is why Sukhoi’s forward swept wing demonstrator was called the S-37.