GNU Unifont is a bitmap font. It provides a fixed glyph for every code point in the BMP. It also covers additional code points in other planes.
I am guessing this is useful for writing editors that can edit Unicode text without knowing anything about various languages and their conventions. Authors who try to use this font to compose documents in (say) devanagari will have to learn the Unicode characters "in the raw", because I don't see a shaper for devanagari, so they won't get feedback that looks like real text.
Amusingly, here it is also BitMap [1]. Why they use an obsolete noncompressed proprietary format instead of PNG I don't know.
Edit: looks like it's because BMP supports 1-bit packed pixels and ~~PNG doesn't~~ (Edit to edit: this is wrong). The file sizes are almost identical; the 8x difference in the number of bits is exactly balanced by PNG compression! On the other hand, PBM [2] would've been a properly Unixy format, and trivial to decode, but I guess "the browser knows how to render it" is a pretty good argument for BMP. macOS Preview, BTW, supports all the NetPBM formats, which I did not expect.
Maybe they set everything up before png was popular and never changed the workflow since then (or didn't care about the website to adjust anything)? After all, the PNG is only about 2 years younger than the font
GNU Unifont is a bitmap font. It provides a fixed glyph for every code point in the BMP. It also covers additional code points in other planes.
I am guessing this is useful for writing editors that can edit Unicode text without knowing anything about various languages and their conventions. Authors who try to use this font to compose documents in (say) devanagari will have to learn the Unicode characters "in the raw", because I don't see a shaper for devanagari, so they won't get feedback that looks like real text.
If anyone can explain this better, please do!