It currently says "Discussions cannot be embedded yet." Since Flow is no longer under active development, the "yet" should be removed.

Other less crucial wording changes:

• Change "embedded" to "transcluded" since that is the common term for this action.
• Change "discussions" to "Structured Discussions" or "Flow boards", or some other term that doesn't imply the now-outdated vision that all discussions use Flow.

This is "flow-embedding-unsupported" in i18n/en.json