What are the analogues of docs.google.com for local deployment in the office?

Question

Google

Is there an analogue of a cloud office for deployment in an office network? Preferably open source. Or other software that allows several employees to work simultaneously with one document, taking into account the visibility of changes by another employee instantly, like in Google Docs.
Important note: The software must be deployed on the company's local network. Management will not approve online services.