Despite not being directly used by the usual Jenkins users, the repo.jenkins-ci.org service is crucial for any contributor to the Jenkins project as it hosts all the development dependencies and released binaries as the source of truth.
The entire Jenkins Infrastructure uses this repository to build and publish Jenkins itself, and also all of its plugins and side projects.
This migration is an important requirement to ensure that JFrog is able to monitor the service and provide the best availability and infrastructure health. If you are curious or interested, you can find more details on the Jenkins Infrastructure issue tracker: Jenkins Infrastructure Helpdesk Issue #3288
This is a companion discussion topic for the original entry at https://www.jenkins.io/blog/2022/12/09/jfrog-maintenance/