CorkPastAndPresent.ie (an essential site for anyone with Cork City and county ancestors).
It's the McDonnell's Index of Births, Marriages and Deaths, which includes bmd announcements published in The Constitution and Cork Advertiser newspaper from 1828 to 1830.
These transcriptions are the work of a local researcher, Paschal McDonnell. A member of the Local Studies team told Irish Genealogy News that this date was chosen as a continuation of the work carried out by renowned Irish genealogist Rosemary ffolliatt whose transcriptions of earlier editions appeared in her magazine The Irish Ancestor (published 1969–1986).
Mr McDonnell started his transcription work with the 1828 announcements and, as far as I can see from looking at his Indexes, continued with the following two years. This isn't clear from the filenames which suggest that events for 1828 alone are included. Click the image above to choose from the Births, Marriages and Deaths pdf (freely downloadable).
The Cork Constitution is not currently included in either of the two big online Irish newspaper databases (IrishNewsArchive.com or BritishNewspaperArchive.co.uk/FindMyPast) but they are available to view at the Local Studies Rooms at Cork Central Library on Grand Parade, Cork; the holding includes bound volumes of the paper run, with some gaps) from 1825 to 1922, while microfilmed copies can be consulted for 1823, 1826-1833, 1835-1837, 1839-1848.