[Makhil]

Research 1: you can see the races of other planets (yes it means that without this research, it won't show on the gal pages)
Research 2: you can see the planets government type
Research 3: you can sign a peace treaty with other planets : can't attack each other (can still cov op)
Research 4: you can sign a trade agreement with other planets (only after signing a peace treaty): exchange resources at 0% taxe
Research 5: you can sign a Mutual Defense Treaty with other planets (only after signing a trede agreement) and enjoy a -1 eta for def fleets on each other.

Treaties can be canceled anytime.

The number of treaties you can sign could depend on the number of constructions you build: embassies. 1 embassy allows to sign the 3 types of treaties with 1 planet.

You can only sign a treaty with another planet if it also has the research and building allowing it.