FLStudio Producer Edition v12.5.1 [build 165] - 32 Bit[/s:3qw81m9k]
Edit 2: I actually just updated to FL 20 (I'm glad I came here, because I only just discovered that it existed), but I'm still getting this ...
FLStudio himself. It's likely he used that same soundfont player very often, and with Undertale's reputation of having a legendary soundtrack, I think that attests to its relevance and competence as a tool for producers.
I know ...