Feature summary: Use the mensural notation features in Score extension (Lilypond)

Use case(s):
I was trying to transcribe some public-domain music from the 17th century on Wikisource, and I found that Lilypond has the functionality to transcribe it, but only if I put

\include "gregorian.ly"

in the Lilypond source. Including the file is not possible in Mediawiki; obviously it would be highly undesirable for editors to be able to include arbitrary files in Lilypond rendering, security for Lilypond seems to be hard enough as it is.

Is there a reasonable alternative way to allow Mediawiki scores to use the historic notation marks usually enabled by "gregorian.ly"?

Benefits: This particular functionality would be useful, especially on Wikisource. Unsurprisingly, a lot of public-domain music scores are written in historic notation forms. Historic notation often can't be translated one-for-one to modern notation. For instance, some of it does not indicate absolute pitch/note name at all, some has durations that are flexible in specific ways, some can be played several different ways, and the pieces I am transcribing have finalis marks, section markers with a set of meanings that overlap with several different modern notations (there are also some historic notations of un- or poorly-known meaning). This is why musicians performing, say, Gregorian chant, usually use Gregorian notation (example). It is possible to write a modern interpretation of the piece in modern notation, but not the historic score.