{{Better source needed}} is very similar to {{Citatiion needed}}, but we currently don't show a special context item in VE for it.

Citation needed	Better source needed

The templates suggests that the user may want to consider removing the existing reference, but I don't think we should automate this because (1) the existing reference my partially cover the claim and be helpful as a secondary reference and (2) there may be multiple references and it isn't clear which one to remove (e.g. https://en.wikipedia.org/w/index.php?title=Topological_space&oldid=1361655787#History)

{{Better source needed}} is used ~27,000 times, and exists in ~60 languages.

If we add a generic option to the config that lets users override the title/body, then this could be used for this template or any other variations that may exist.