Ctrl+Pause should send a Break symbol. This doesn't work properly on Windows. Fixed upstream here: https://github.com/TigerVNC/tigervnc/commit/cc945566b4e384bbbe3b0198320bcb50fb6db40a
Yup. I'm now getting getting proper Break for Ctrl+Pause. And just Pause (or Shift-Pause) still gives the regular Pause symbol.