The individual tunes are in files with names of the form VPPPN_Title.abc, where V is the volume (or "Part") number, PPP is the page number, N is number of the tune on the page, and Title is the value of the T: header line with spaces replaced with '_'. N is 0 for a few files that don't contain tunes, such as the title page. The tunes have numbers, but the minuets and dance tunes are both numbered 1-12, which is used for the X: value but isn't used in the file name because it isn't unique or useful for the sequential order. There are a few files just named VPPPN_.abc, with no title; they are placeholders for parts of tunes placed on a second page, to indicate that the music was transcribed but is in the earlier file. (Some tunes were placed on two facing pages.)
The titles in this collection are mostly upper case, though a few contain some words in lower case (mostly in parentheses). Capitalization in the file names matches current practice: important words are capitalized, words like articles and common prepositions are all lower case. Initial articles are omitted in file names but are present in tunes' T: lines, in lower case to match the occasional practice that makes it easy for software to ignore them.
Some of the music in this collection has notation which not all ABC software (or modern musicians) understands properly. For these tunes, two transcriptions may be present: The "-V2" version has the ABC 2.0 notation, typically proofread with the abcm2ps formatter. The "-V1" version is restricted to ABC 1.7 features, and may entail some rewriting or omission of unrepresentable annotations, typically proofread using the last abc2ps formatter, or its jcabc2ps clone. Also, the -V1 versions have '-' after the initial 5 digits, while the -V2 versions have '='. This is to make it easier to distinguish them in file-name patterns, such as are used in the Makefile. You may want to strip off the initial digits and the [-_=] characters, to get just the title as the file name.
Few of the tunes in this collection have attributions, and the cotillion tunes rarely have titles. Some tunes are well known, and occasionally the modern titles are added as subtitles. Howe may have been the composer of some of the tunes, but we don't really know.