the photo in burden.ppm is "selective focus photography snowflakes" by aaron
burden. it can be found online at
https://unsplash.com/photos/selective-focus-photography-snowflakes-9yhy1FXlKwI.
its license can be found online at https://unsplash.com/license.

the icon in pointer.ppm is by me :)

the font in terminus-bold-18x10.psf is the "terminus" font, in bold weight, at
18x10. it can be found only at https://terminus-font.sourceforge.net/ and is
under the license in terminus-ofl.txt (the sil open font license v1.1).