Some further research turned up a demo of lilydumper and lilyplayer. While the lilyplayer demo of an existing dump file produced by lilydumper works, lilydumper itself, alas, does not appear to.
lilydumper - https://github.com/henriyulianto/lilydumper lilyplayer - https://github.com/s-d-m/lilyplayer They seem a bit abandoned. Meanwhile... blissfully displaying my ignorance, no doubt... I wonder (and filed an enhancement / feature request issue) if it would be worth adding a "verbose" option that causes SVGs to add in classes (or other attributes) for each note or rest glyph. A sequence number "class" based upon whatever the smallest logical division of a beat is (within reason), that acts like a figurative timestamp -- independent of tempo, and a duration "class". All notes starting at the same offset would get the same sequence number, and the durations would be whole, half, quarter, eighth, dotted, etc. They might not cover every possible way of writing scores but would cover a significant number. It would seem that, with relatively little math, this could be mapped to the corresponding MIDI...
