news1 appears in the "wordfreq" file compiled by Alexandre Girardi from the Mainichi Shimbun. (See the Monash ftp archive for a copy.)

nf15 this is an indicator of frequency-of-use ranking in the wordfreq file. "xx" is the number of the set of 500 words in which the entry can be found, with "01" assigned to the first 500, "02" to the second, and so on.