This is apparently a manuscript created in the 1600s. The Register received two transcriptions and printed the one by Samuel H. Parsons of Middletown. The preamble to the article (it is not clear who wrote which parts when) says:
In the Town of Windsor, in Connecticut, copied from the first book of Records in Windsor, under the date of 18 May, 1674, and with the following preamble by the recorder:
"May 18 1674. I here set down a new genealogy of children that
The article is a listing by families in the format Husband, m. wife, date, children born. Despite the 1674 date above, the lists of children go to at least 1677, with some dates up to 1690. A footnote in the NEHGR indicates that words and sentences in brackets are in pencil in Mr. Parson's work and, "apparently made at a later date than the body of the work." It's unclear whether this means they were added by Parsons in the 1800s, or by the original compiler.
Another set of Windsor Vital Records lists as its original source the "first book" at Windsor. A comparison of the records that transcription shows as occurring prior to 1674 shows a number of differences: many of the records are in both places, but many children are spelled differently; many records are in one source or the other -- sometimes whole families, sometimes just a child or two; and this record set directly links husbands and children with the wife (including maiden name) and death records.
Dates are all listed Old Style.