Windows Bitmap extension vga, rl4, rl8

[jenderek]

Hello,

some days ago i handle my Windows Bitmap collection with different tools.
I also use the XnView graphic tool. On the page of XnView about supported formats
there are listed six extensions:
bmp,rle,vga,rl4,rl8,sys
BMP is the standard suffix. I found examples with RLE suffix for run length
encoded examples. I also found some Windows 9M boot messages pictures with
SYS suffix. Unfortunately i found no examples with VGA, RL4 and Rl8 suffix.
Where can i find such samples? Under which conditions these three extensions
are used? I myself believe that RL4 is used for run length encoded samples
with 4 bit color depth and RL8 is used for run length encoded samples
with 8 bit color depth. Is this true?

Thanks for tips and advice.
Jenderek