"Announcements are public pronouncements on matters of general interest, such as the effective dates of temporary regulations, clarification of rulings and form instructions. They are issued when guidance of a substantive or procedural nature is needed quickly. . . . Announcements are identified by a two digit number representing the year and a sequence number." (Miscellaneous Documents, IRM § 184.108.40.206.4.1
"An announcement is a public pronouncement that has only immediate or short-term value." (Annoucement Defined, IRM § 220.127.116.11.4)
"IRS Announcements are public pronouncements written by chief counsel attorneys that have only immediate or short-term value. They are published in the Internal Revenue Bulletin and are not included in the Cumulative Bulletin." (Inventory of IRS Guidance Documents — A Draft, Tax Notes Today)
The following citation resources may be informative.
Below are links to select sources offering announcements.