I searched for "Yamaha" "meta-event" "43 73" on DuckDuckGo and found several Yamaha models in the results. (Some search results were from shady manual sites, so I just put the model numbers from those results into the Yamaha Manual Library search instead to get the manuals directly from Yamaha.)

That lead me to the following PDF manuals. Each manual has a section "Song Meta Event List" and sub-section "YAMAHA META Event" that lists meta events that start with FF 7F len 43 73. The first manual (CVP-900 Data List) has six meta events listed. The rest of the manuals have two or three metaevents listed from that set of six. There were more models coming up at the bottom of the DuckDuckGo search results, but I wasn't motivated to find manuals for all of them, since it seems like the first manual has the superset of metaevents.

CVP-900 Data List
TYROS Data List
TYROS3 Data List
Tyros4 Data List
PSR-2100/PSR-1100 Data List
PSR-S900/S700 Data List

I have been following the posts here about these Yamaha meta events with a little bit of interest.

In 2006, I posted an analysis of Yamaha PSR-225 Bulk Dump messages. The Yamaha PSR-225 lets you record user songs, but doesn't have any way to export them. The user songs can only be dumped in a bulk dump and restored from a bulk dump. However when I analyzed the song data bulk dump, I found you could piece together blocks of data to build a MIDI file that contained a user song. This MIDI file includes Sequencer-Specific meta events whose data bytes begin with hex 43 76. (I called them "proprietary metaevents" on that page.) The meta events I analyzed seem similar to some Yamaha XF ones but not exactly the same.

At the time, I couldn't find any information about those hex 43 76 meta events, so it's interesting to me to read about these other similar Yamaha meta events. Maybe you'll find the meta events I analyzed of some interest. Although, if they were only used in this internal bulk dump, they're unlikely to be seen in actual MIDI files. I doubt if anyone other than me ever built a MIDI file out of a Yamaha PSR-225 bulk dump.

It looks like these are part of the Yamaha XF spec? I may have just learned something new!

http://www.jososoft.dk/yamaha//pdf/xfspec.pdf

It appears 7 times in this spec document with good descriptions of each.