User blog comment:MisterWoodhouse/The first migrations to the Unified Community Platform/@comment-26467247-20201204155922/@comment-1038387-20201204165941

The old SourceEditor is no longer supported as of MW 1.32, and UCP uses 1.33. The 2017 Editor (Visual and Visual - Source) has a FaR built in, but it's not multiline. See "this page for the status of custom scripts.