Help with RGB color scheme

I'm fiddling with fonts in something, and I've encountered this weird color scheme formatting. RGB has 3 numbers, but this has 4, and I have no idea how to read it. Anybody knows?

<Font Name="OMW" Type="RegularBold" Resolution="18_1_Normal" >
<Display Color="38,255,114,255" OutlineColor="40,20,0,255"/>
</Font>

>>1
It's a secret code that makes the text invisible. It's for compatibility with IE6, so you can just remove it if you aren't working with prehistoric browsers.

red green blue alpha