I would assume all data that companies can get their hands on. Fun fact, I installed Windows 10 in a VM a few days ago and it had like 5 "do you want to send us optional data or only the required data? Y/n" screens in the installer alone 💀
kept, and used long term
Probably until you request it's deletion using a law like GDPR. Data is valuable because:
it's used in targeted advertising
it can be sold to data brokers
it can be sold to government agencies
depending on the type of data, it might be usable for AI training/can be sold to AI companies