Idea

Use one renovate.json file for all the repos under https://gitlab.cee.redhat.com/dragonfly.

This can be done with an inherited config to apply one config for all repos. See https://konflux.pages.redhat.com/docs/users/mintmaker/user.html#inherited-config & https://docs.renovatebot.com/config-overview/#inherited-config 

Implementation

Ideally, the renovate file/s should be stored under renovate-config repo for easy inheritance. However, it was easier to follow and use when it was moved to the general https://gitlab.cee.redhat.com/dragonfly/tools repo and a renovate-config directory.
Using one renovate file is good, but it doesn't match the RHWA repos' needs, as some of them need to rpm-lockfile-prototype rpms.in.yaml for RPM updates (see RHWA-540 for more) whenever a base image has been updated.
So we have moved to two files that act as presets that the renovate file of each repo can extend

    "extends": [
        "local>dragonfly/tools//renovate-config/default"
    ] 

For more background, see the Slack message at https://redhat-internal.slack.com/archives/C04PZ7H0VA8/p1767690114083369?thread_ts=1766471146.818369&cid=C04PZ7H0VA8 and how it was developed from one idea to a general and better maintainable preses implementation.