Comment 21 for bug 132417

Its very simple actually.
Fontconfig is just a mess.
It can happly pick up a preffered that misses glyphs that
document needs.

So to fix the '>=' issue I removed the 'ttf-symbol-replacement' font
which apparently isn't such a correct symbol replacement.

After that, fontconfig picked up as the Symbol font the
'/usr/share/fonts/X11/Type1/Symbol.pfb'

Which belongs to

maxim@maxim-laptop:~$ sudo dpkg -S /usr/share/fonts/X11/Type1/Symbol.pfb
xfonts-mathml: /usr/share/fonts/X11/Type1/Symbol.pfb

Hopefully, if you have that package installed the same will happen and the <= glyph will render normally again.

Now about some homeworks I had that were in hebrew, and were missing most Hebrew fonts
(like the one I attached here)

These files were using the Nimbus Roman No9 L to render most fonts and its very bad Times replacement, becuse it misses Hebrew glyphs.

I hoped to install MS fonts from 'ttf-mscorefonts-installer', but If you installed them in hope that you will get correct fonts, font-config won't pick these fonts.
There is a forest of setting files in /etc/fonts that make it select anything but not these fonts,

I just back-uped and removed the /usr/share/fonts/type1/gsfonts/ which contain that dreadful 'Nimbus Roman No9 L' font that replaces Times New Roman, and probably few more fonts and installed 'ttf-mscorefonts-installer' and now all my docs show up correctly (also with ttf-symbol-replacement, and 'Symbol' isn't mapped to MS font, but the one I told above seems to work fine)

The point it that these replacements don't contain nearly as much glyphs as needed unlike MS fonts and fonconfig isn't smart enough to pick _any_ font that has these glyphs. I am not picky about fonts, I just need to be able to read the document, in this case in Hebrew.

Instead of MS fonts, you can use the Dejavu fonts at least which are installed, and once again fontconfig doesn't pick them.
These fonts have good Unicode coverage, but still don't render everything correctly, in that old homework.
Once again to let these fonts to be used you need to apply some magic to /etc/fonts.
(They seems to be used if I just remove the /usr/share/fonts/type1/gsfonts/ and the MS fonts)