One (extreeeemely pedantic) difference is that (I think) HDMI begins and ends its vsync pulses when the preceding hblank begins, whereas VGA begins and ends the

One (extreeeemely pedantic) difference is that (I think) HDMI begins and ends its vsync pulses when the preceding hblank begins, whereas VGA begins and ends them slightly later when the preceding hsync pulse begins (I documented this at https://nyanpasu64.gitlab.io/blog/crt-modeline-cvt-interlacing/#vsync-pulse-timing-within-a-scanline https://nyanpasu64.gitlab.io/blog/crt-modeline-cvt-interlaci...). I also think that DP rouuuughly reflects CRT timings complete with active vs. blanking intervals, but doesn't actually have a fixed pixel clock (perhaps it does? I didn't quite figure out synchronous/asynchronous pixel transmission when reading the spec) and doesn't transmit hsync pulses once per scanline.