3GPP 21.900 v20.0.0 — the document's own text
8.4 Decision announcement
Taught in 8. How a 3GPP meeting decides, and the word it decides in (How standards actually get made, in depth).
When a decision is made (Agreed, rejected, postponed, ...) a clear notification on what has been agreed shall be sent on the main mailing lists of the relevant groups.