[gadflyinyoureye]

Maybe because so is the 5th of a scale, and this has 5/8ths of the features of Jira?

[riffraff]

For potentially confused people out there: some countries/musical traditions use a do-re-mi-fa-so-la-ti(si) scale, rather than do-re-mi-fa-sol-la-si or a-b-c-d-e-f-g.

This has the interesting side effect that the word solfege (sol-fa) makes little sense.

https://en.m.wikipedia.org/wiki/Solf%C3%A8ge#Note_names