I really like the font configuration (appearance) of the documentation for
microtype package (see here). How do I find out the combination they're using? (I will fix the protrusion etc later but first I need to select the fonts etc. that they're using.)
You can look at the source code for the documentation here: http://mirrors.xmu.edu.cn/CTAN/macros/latex/contrib/microtype/microtype.dtx
If you don't have access to document sources, some pdf viewers can show you what fonts are used. I've tested with AdobeReader and PDF-XChange-viewer and under Properties of the document you will find the list of fonts. Here you have the output from microtype manual under Xchange-viewer.
Just a problem, then you need to find how to use them in your document.