A possible plan:
- Find a suitable replacement to EasyTimeline (maybe Charts)
- Write a help page with all the known usages and instructions on how to convert them
- By consulting the help page, determine whether we can replace all the features we use/want, and decide to make the change
- Announce the need to migrate and overall plan
- Provide a tool to find all current content to migrate (T137310: Provide tracking category or page property for <timeline> uses?)
- Provide a tool/guide to migrate current content over
- Warn people and wait (six months? a year?)
- Disable EasyTimeline