[knuthsat]

This is computer modern optimized for printing. It’s not bad, the pixels are constructing the glyphs in a way that makes them good for printing.

Bitmap version of the font, I guess.

[gkbfj]

DVI files do not contain fonts. What happened here is that the DVI to PDF conversion targeted a low resolution bitmap output (for screen/download, not for printing). The vector font specified by the DVI file was rasterized at that point. Later, PDF compatible (PostScript) vector versions of the Computer Modern fonts became available.

https://wearables.cc.gatech.edu/resources/latex2pdf.html