[mhw]

Good question - it's obviously still widely enough used that the need to decode the format lives on.

Many years ago I wrote the code to support PBM/PGM/PPM images for Mozilla (https://bugzilla.mozilla.org/show_bug.cgi?id=117983). They never got that much traction on the web though, and so support for that image format was dropped: <https://bugzilla.mozilla.org/show_bug.cgi?id=197530>.