Each tune is here with two names. One has the format N-D_N-K-B-S.abc, where N is the 4-digit dance number in the booklet, D_N is the dance's name (with underscores for the spaces), K is the tune's key, B is the number of bars in the dance, and S is tne number of staves used for the tune. The second file name has the form T_N-K-B-S.abc, where T_N is the tune's name, and -K-B-S.abc are the same as for the dance.
Some might have a different B=bar count. This typically happens when the tune is played twice for once through the dance. The book often used the clumsy approach of having two endings for such tunes; the first with the initial pickup notes repeated, and the 2nd with just a long last note. Such cases are often simplified to have just the tune with a final repeat sign, to simplify reading and save a bit of space on small screens.