The list of letters in UTF-8 format that is currently used in the fonts can be optained with:

ruby -e '((32..127).to_a + (128+32..383).to_a).each_with_index{|c,idx| print [c].pack("I"); if ((idx+1) % 16 == 0) then print [10].pack("I") end }' | recode "UCS-4LE..UTF-8"