Can you please elaborate on your question? Do you want to know what languages SailPoint uses to build the front end and back end of IDN, or what languages the community uses to integrate with IDN?
Since IDN is a SaaS product, interacting with it is done via REST APIs. This means you can use any programming language to interact with IDN. Like most SaaS products, it shouldn’t really matter what technologies are used to build it, since users will be interacting with the product through APIs which are language agnostic.