Redis is being used to handle rate limiting. Recently, Redis dropped their open-source license, so new versions will not be open-source, and likely won't be packaged in any Linux distributions. There are two forks main forks that came out of this change that I expect will get some traction in Linux packaging:
Valkey, a fork by The Linux Foundation which has industry support and will continue on the roadmap to add new features
Redict, which aims to keep the feature scope where it is and focus on stability and long-term maintability
Another alternative would be memcached or similar.