Does anyone know why Win32 dialog boxes were assigned the class name "#32770"?

I can't find anything about it at all. Microsoft documentation doesn't provide any context. Nobody seems to have asked this question before.

@codecat The WINE header files reference "Undocumented Windows page 418" as a source for these -- if you can track that down, that might have more context...
@Ninji Ohhhh good find! I found some info to go on, thank you! Maybe it's interesting to write a blogpost about this 😅